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224 results on '"H-mode"'

201. Reflections on fourteen cryptic issues concerning the nature of statistical inference

Subjects
decision analysis, INTERVAL ESTIMATION, PROBABILITIES, H-MODE, epistemic uncertainty, ENERGY CONFINEMENT, Bayesian analysis, possibility theory, prior distributions, THRESHOLD DATABASE, BELIEF, nonparametric statistics, time series analysis, ITER, likelihood approach, BURNING PLASMA, PARTIAL LIKELIHOOD, objectivistic and personalistic interpretation of probability, distributional inference, semiparametric statistics, DYNAMIC-SYSTEMS, foundations of probability theory and statistics
Abstract

The present paper provides the original formulation and a joint response of a group of statistically trained scientists to fourteen cryptic issues for discussion, which were handed out to the public by Professor Dr. D.R. Cox after his Bernoulli Lecture 1997 at Groningen University.

Published
2003

203. H-mode access during plasma current ramp-up in TCV

Author

Y. Martin, R. Behn, I. Furno, B. Labit, H. Reimerdes, and the TCV Team

Subjects
H-mode, Physics, Nuclear and High Energy Physics, Divertor, Mode (statistics), Plasma, Atomic physics, Condensed Matter Physics, L-H transition, X-point height, TCV tokamak, Power (physics), Plasma current
Abstract

A recent TCV experiment has investigated the dependence of the L–H transition threshold power on the plasma current ramp-rate and the X-point height above the divertor target, which both have previously been seen to affect the transition behaviour. Systematic scans in ohmically heated plasmas do not show any dependence on the plasma current ramp-up rate. In contrast, the threshold power is found to increase by a factor of two while the X-point is moved from about 10 cm up to 35 cm above the vessel floor. However, further increase, up to 60 cm, does not lead to any further increase of the required power. The Fundamenski et al model is tested against the measurements. Estimates of the Wagner number (Wa) at L–H transitions are generally close to unity, in accordance with the model. In contrast, estimates of Wa before the L–H transition, i.e. in L-mode, do not show the expected evolution towards unity.

Published
2014
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204. The role of radial electric fields in the tokamaks TEXTOR-94, CASTOR, and T-10

Author

Van Oost, G., Gunn, J. P., Melnikov, A., Stockel, J., Tendler, Michael, Van Oost, G., Gunn, J. P., Melnikov, A., Stockel, J., and Tendler, Michael

Abstract

Radial electric fields (E-r) and their role in the establishment of edge transport barriers and improved confinement have been studied in the tokamaks TEXTOR-94 and CASTOR, where E-r is externally applied to the plasma in a controlled way using a biased electrode, as well as in the tokamak T-10 where an edge transport barrier (H-mode) is obtained during electron-cyclotron resonance heating (ECRH) of the plasma. The physics of radial currents was studied and the radial conductivity in the edge of TEXTOR-94 (R = 1.75 m, a = 0.46 m) was found to be dominated by recycling (ion-neutral collisions) at the last closed flux surface (LCFS) and by parallel viscosity inside the LCFS. From a performance point of view (edge engineering), such electrode biasing was shown to induce a particle transport barrier, a reduction of particle transport, and a concomitant increase in energy confinement. An H-mode-like behaviour can be induced both with positive and negative electric fields. Positive as well as negative electric fields were shown to strongly affect the exhaust of hydrogen, helium, and impurities, not only in the H-mode-like regime. The impact of sheared radial electric fields on turbulent structures and flows at the plasma edge is investigated on the CASTOR tokamak (R = 0.4 m, a = 0.085 m). A non-intrusive biasing scheme that we call separatrix biasing is applied whereby the electrode is located in the scrape-off layer (SOL) with its tip just touching the LCFS. There is evidence of strongly sheared radial electric field and E x B flow, resulting in the formation of a transport barrier at the separatrix. Advanced probe diagnosis of the edge region has shown that the E x B shear rate that arises during separatrix biasing is larger than for standard edge plasma biasing. The plasma flows, especially the poloidal E x B drift velocity, are strongly modified in the sheared region, reaching Mach numbers as high as half the sound speed. The corresponding shear rates (approximate to5, QC 20100525

Published
2001
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205. Integrated real-time control of MHD instabilities using multi-beam ECRH/ECCD systems on TCV

Author

Olivier Sauter, Faa Federico Felici, G. P. Canal, B. P. Duval, Stefano Coda, Timothy Goodman, JX Rossel, and Control Systems Technology

Subjects
Physics, Nuclear and High Energy Physics, Tokamak, H-Mode, DIII-D, Rational surface, Sawtooth Period, Beta, Sawtooth wave, Pulsed power, Cyclotron Current Drive, Condensed Matter Physics, Stabilization, law.invention, Control theory, Real-time Control System, law, Plasmas, Control system, Neoclassical Tearing Modes, Discharges, Magnetohydrodynamics, Diii-D
Abstract

Simultaneous real-time control of multiple MHD instabilities is experimentally demonstrated in the TCV tokamak. Multiple sources of EC heating and current drive, injected through real-time controlled launchers, are used to stabilize 3/2 and 2/1 neoclassical tearing modes (NTMs) rapidly after their appearance. Control of the sawtooth instability using a new sawtooth-pacing technique is demonstrated, providing precise control of the time of appearance of the sawtooth crash. Efficient NTM preemption can then be performed by applying pulsed power on the mode rational surface at the time of the seed-island generating sawtooth crash. These three elements are combined into one integrated control system which can simultaneously control the sawtooth period, preempt the formation of NTMs and suppress these if they appear.

Published
2012
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206. Full tokamak discharge simulation of ITER by combining DINA-CH and CRONOS

Author

J.F. Artaud, J.B. Lister, R. R. Khayrutdinov, S.H. Kim, V. Basiuk, V. Dokuka, and V.E. Lukash

Subjects
Transport Simulations, H-Mode, Safety factor, Tokamak, Materials science, DIII-D, Nuclear engineering, Plasma, Current source, Condensed Matter Physics, Hybrid, law.invention, Database, Plasma Equilibrium Responses, Nuclear Energy and Engineering, Jet, Scenarios, Jt-60U, Physics::Plasma Physics, law, Electromagnetic coil, Current (fluid), Diii-D, Code Simulations, Voltage
Abstract

A full tokamak discharge simulator has been developed by combining a free-boundary equilibrium evolution code, DINA-CH, and an advanced transport modelling code, CRONOS. The combined tokamak discharge simulator provides a full simulation of a whole tokamak discharge, including non-linear coupling effects between the evolution of the free-boundary plasma equilibrium and transport. The free-boundary plasma equilibrium evolution is self-consistently calculated with the plasma current diffusion, in response to currents flowing in the PF coils and the surrounding conducting system. The heat and current source profiles calculated taking the free-boundary plasma equilibrium are used for the plasma transport. The constraints in operating a tokamak, such as the PF coil current and voltage limits, are taken into account. The potential of the combined tokamak discharge simulator is demonstrated by simulating whole operation phases of the inductive 15 MA ELMy H-mode ITER scenario 2. Issues related to ITER operation, such as respecting the coil current limit, vertical instability and poloidal flux consumption, are investigated. ITER hybrid mode operation is studied focusing on the capability of operating the plasma with a stationary flat safety factor profile.

Published
2009
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207. Measurement of 3-D Mode Structure of the Edge Harmonic Oscillations in CHS using Beam Emission Spectroscopy

Author

T. OISHI, S. KADO, M. YOSHINUMA, K. IDA, T. AKIYAMA, T. MINAMI, K. NAGAOKA, A. SHIMIZU, S. OKAMURA, and null CHS group

Subjects
Physics, edge transport barrier, density fluctuation, Toroid, Radius, Condensed Matter Physics, Magnetic field, H-mode, compact helical system, Physics::Plasma Physics, beam emission spectroscopy, Harmonic, Emission spectrum, Magnetohydrodynamics, Atomic physics, magnetohydrodynamics, Harmonic oscillator, Beam (structure), edge harmonic oscillation
Abstract

The 3-D spatial structure - radial locality and poloidal /toroidal mode numbers - of the magnetohydrodynamic fluctuation called “edge harmonic oscillation (EHO)” in the compact helical system (CHS) was investigated using beam emission spectroscopy (BES) as the diagnostic method of the local density fluctuations and the magnetic probe array. We found two groups of harmonic oscillations in CHS, one with a frequency of 4.0 kHz and a harmonic located in the edge region of the normalized minor radius ρ = 0.95 near the rotational transform ι = 1 surface, and the other with a frequency of 3.5 kHz and a harmonic located in the core region ρ = 0.53 near the ι = 0. 5s urface. The magnetic probe signals showed that the poloidal/toroidal mode numbers of the edge mode and the core mode were −1/ 1a nd−2/1, respectively. They were consistent with the rotational transform of the magnetic field at the locations of those modes. c

Published
2007

208. Analysis and expansion of the quasi-continuous exhaust (QCE) regime in ASDEX Upgrade

Author

Michael Faitsch, Thomas Eich, Georg Friedrich Harrer, Elisabeth Wolfrum, Dominik Brida, Pierre David, Mike G Dunne, Luís Gil, Benoit Labit, Ulrich Stroth, ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, and EUROfusion MST1 Team

Subjects
Nuclear and High Energy Physics, confinement, modes, jet, turbulence, magnetic confinement, separatrix, Condensed Matter Physics, h-mode, tokamak, qce
Abstract

The quasi-continuous exhaust (QCE) regime, formerly known as either type-II ELM or small ELM regime is studied in ASDEX Upgrade. The regime is a natural type-I ELM-free H-mode. The operational space of QCE discharges in ASDEX Upgrade with respect to their separatrix conditions and their power exhaust capabilities are presented. A significant broadening of the power fall-off length is observed, correlating to an increased separatrix density and pressure. Moreover, the possible reactor relevance of this regime is demonstrated by expanding the operational space to low edge safety factor and demonstrating the benign tungsten impurity behaviour. A discharge without any type-I ELM from start to end reaching a partially detached divertor at high normalised energy confinement time is presented.

209. Mixed hydrogen-deuterium plasmas on JET ILW

Author

I. H. Coffey, D. B. King, D. L. Keeling, M. Baruzzo, L. Horvath, E. R. Solano, M. Maslov, D. Valcarcel, E. Belonohy, Jet Contributors, L. Garzotti, E. Viezzer, James Buchanan, K. Kirov, S. A. Silburn, S. Hall, Ivo S. Carvalho, C.D. Challis, Samuli Saarelma, C. F. Maggi, K. Cave-Ayland, E. Joffrin, I. Balboa, J. C. Hillesheim, E. Delabie, Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, EUROfusion Consortium, European Union (UE). H2020, and Ministerio de Economía y Competitividad (MINECO). España

Subjects
Nuclear and High Energy Physics, Materials science, Hydrogen, chemistry.chemical_element, 7. Clean energy, 01 natural sciences, h-mode, 010305 fluids & plasmas, power, Physics::Plasma Physics, jet, 0103 physical sciences, 010306 general physics, isotope, Jet (fluid), Isotope, density profile, Plasma, Condensed Matter Physics, H-mode, Deuterium, chemistry, JET, confinement, Atomic physics
Abstract

A study of mixed hydrogen-deuterium H-mode plasmas has been carried out in JET-ILW to strengthen the physics basis for extrapolations to JET D-T operation and to support the development of strategies for isotope ratio control in future experiments. Variations of input power, gas fuelling and isotopic mixture were performed in H-mode plasmas of the same magnetic field, plasma current and divertor configuration. The analysis of the energy confinement as a function of isotope mixture reveals that the biggest change is seen in plasmas with small fractions of H or D, in particular when including pure isotope plasmas. To interpret the results correctly, the dependence of the power threshold for access to type-I ELMing H-modes on the isotope mixture must be taken into account. For plasmas with effective mass between 1.2 and 1.8 the plasma thermal stored energy (Wth) scales as m 0.1 eff, which is weaker than that in the ITER physics basis, IPB98 scaling. At fixed stored energy, deuterium-rich plasmas feature higher density pedestals, while the temperature at the pedestal top is lower, showing that at the same gas fuelling rate and power level, the pedestal pressure remains constant with an exchange of density and temperature as the isotope ratio is varied. Isotope control was successfully tested in JET-ILW by changing the isotope ratio throughout a discharge, switching from D to H gas puffing. Several energy confinement times (300 ms) are needed to fully change the isotope ratio during a discharge. EUROfusion Consortium Grant Agreement No. 633 053 RCUK Energy Programme (Grant Number EP/I501 045) H2020 Marie-Sklodowska Curie programme (Grant No. 708 257) Spanish Ministry of Economy and Competitiveness (Grant No. FJCI-201 422 139)

210. Radial localization of edge modes in Alcator C-Mod pedestals using optical diagnostics

Author

Theiler, C, Terry, J L, Edlund, E, Cziegler, I, Churchill, R M, Hughes, J W, LaBombard, B, Golfinopoulos, T, and Alcator C-Mod Team

Subjects
edge transport barrier, H-mode, gas puff imaging, spc_edge, Physics::Plasma Physics, I-mode, plasma instabilities, optical plasma diagnostics
Abstract

Dedicated experiments in ion cyclotron range heated enhanced D-alpha (EDA) H-mode and I-mode plasmas have been performed on Alcator C-Mod to identify the location of edge fluctuations inside the pedestal and to determine their plasma frame phase velocity. For this purpose, measurements from gas puff imaging (GPI) and gas puff charge exchange recombination spectroscopy (GP-CXRS) have been collected using the same optical views. The data suggest that the EDA H-mode-specific quasi-coherent mode (QCM) is centered near the radial electric field (Er) well minimum and propagates along the ion diamagnetic drift direction in the plasma frame. The weakly coherent mode (WCM) and the geodesic acoustic mode observed in I-mode, on the other hand, are found to be located around the outer shear layer of the Er well. This results in a weak plasma frame phase velocity mostly along the electron diamagnetic drift direction for the WCM. The findings in these EDA H-mode plasmas differ from probe measurements in ohmic EDA H-mode (LaBombard et al 2014 Phys. Plasmas 21 056108), where the QCM was identified as an electron drift-wave located several mm outside the Er well minimum in a region of positive Er. To explore if instrumental effects of the optical diagnostics could be the cause of the difference, a synthetic diagnostic for GPI is introduced. This diagnostic reproduces amplitude ratios and relative radial shifts of the mode profiles determined from poloidally and toroidally oriented optics and, if instrumental effects related to GP-CXRS are also included, indicates that the measured location of the QCM and WCM relative to the Er well reported here is only weakly affected by instrumental effects.

211. ITER baseline scenario investigations on TCV and comparison with AUG

Author

[creator not identified], Sauter, Olivier, Vallar, Matteo, Labit, Benoît, Karpushov, Alexander, Bagnato, Filippo, Coda, Stefano, Merle, Antoine, Pütterich, Thomas, Bobkov, Vladimir, Dunne, M. G., Lang, P. T., MARASCHEK, Marc, McDermott, R. M., Neubert, Ph., Stober, Joerg, Suttrop, Woflgang, Willensdorfer, M., Voitsekhovitch, Irina, Camenen, Yann, Widmer, F., Eriksson, F., Fransson, E., Mantsinen, Mervi, TCV TEAM, ASDEX UPGRADE TEAM, and EUROFUSION MST1 TEAM

Subjects
H-mode, fusion, ELMs, transport, ITER baseline, tokamak
Abstract

Under the auspices of EUROfusion (WPMST1), the ITER baseline scenario (IBL, [1]) is jointly investigated on AUG and TCV. While the AUG results were presented at the last IAEA FEC [2], this contribution focuses on the recent results obtained in TCV and related integrated modelling results. Such developments in TCV were only possible with the installation of an NBI heating source [3], allowing ELMy H-modes at ITER relevant N. The IBL scenario is mainly characterized by low q95 (3.0-3.6), high positive triangularity (>0.35) and relatively high elongation (>1.65) and normalized beta (N>1.5). In AUG, these combinations lead to very steep and narrow edge transport barriers, when good confinement is obtained, with high pedestal pressure and therefore large type-I ELM crashes. A similar behaviour is also observed on TCV where discharges with similar confinement properties (H98~1) and normalized beta (N~1.8), as those expected for the ITER baseline scenario, have been obtained. TCV IBL performance is mainly limited by (neoclassical) tearing modes, in particular 2/1 modes. We show that they can be avoided with central X3 EC heating at relatively high q95 and moderate N. However, the lack of significant ECH at the high central densities obtained in TCV IBL scenario limits the duration of low q95 cases to about six confinement times. During this time, current density can fully evolve and density usually keeps peaking until (neoclassical) tearing modes are triggered. Integrated modelling results show ITG dominant instabilities in both AUG and TCV IBLs, and show that, in TCV, NBI fuelling also plays a role to sustain the mainly turbulent-driven significant peaked density profiles. The role of profiles, sawteeth and ELMs regarding MHD stability are also discussed. Safe termination of AUG IBL is demonstrated, q95~3 included, consistent with predictive optimization using RAPTOR

212. Gyrokinetic analysis and simulation of pedestals to identify the culprits for energy losses using 'fingerprints'

Author

Kotschenreuther, M., Liu, X., Hatch, D. R., Mahajan, S., Zheng, L., Diallo, A., Groebner, R., Hillesheim, J. C., Maggi, C. F., Giroud, C., Koechl, F., Parail, V, Saarelma, S., Solano, E., Chankin, A., Abduallev, S., Abhangi, M., Abreu, P., Afzal, M., Aggarwal, K. M., Ahlgren, T., Ahn, J. H., Aho-Mantila, L., Aiba, N., Airila, M., Albanese, R., Aldred, V., Alegre, D., Alessi, E., Aleynikov, P., Alfier, A., Alkseev, A., Allinson, M., Alper, B., Alves, E., Ambrosino, G., Ambrosino, R., Amicucci, L., Amosov, V., Sunden, E. Andersson, Angelone, M., Anghel, M., Angioni, C., Appel, L., Appelbee, C., Arena, P., Ariola, M., Arnichand, H., Arshad, S., Ash, A., Ashikawa, N., Aslanyan, V., Asunta, O., Auriemma, F., Austin, Y., Avotina, L., Axton, M. D., Ayres, C., Bacharis, M., Baciero, A., Baiao, D., Bailey, S., Baker, A., Balboa, I., Balden, M., Balshaw, N., Bament, R., Banks, J. W., Baranov, Y. F., Barnard, M. A., Barnes, D., Barnes, M., Barnsley, R., Wiechec, A. Baron, Orte, L. Barrera, Baruzzo, M., Basiuk, V., Bassan, M., Bastow, R., Batista, A., Batistoni, P., Baughan, R., Bauvir, B., Baylor, L., Bazylev, B., Beal, J., Beaumont, P. S., Beckers, M., Beckett, B., Becoulet, A., Bekris, N., Beldishevski, M., Bell, K., Belli, F., Bellinger, M., Belonohy, E., Ben Ayed, N., Benterman, N. A., Bergsaker, H., Bernardo, J., Bernert, M., Berry, M., Bertalot, L., Besliu, C., Beurskens, M., Bieg, B., Bielecki, J., Biewer, T., Bigi, M., Bilkova, P., Binda, F., Bisoffi, A., Bizarro, J. P. S., Bjorkas, C., Blackburn, J., Blackman, K., Blackman, T. R., Blanchard, P., Blatchford, P., Bobkov, V., Boboc, A., Bodnar, G., Bogar, O., Bolshakova, I., Bolzonella, T., Bonanomi, N., Bonelli, F., Boom, J., Booth, J., Borba, D., Borodin, D., Borodkina, I., Botrugno, A., Bottereau, C., Boulting, P., Bourdelle, C., Bowden, M., Bower, C., Bowman, C., Boyce, T., Boyd, C., Boyer, H. J., Bradshaw, J. M. A., Braic, V., Bravanec, R., Breizman, B., Bremond, S., Brennan, P. D., Breton, S., Brett, A., Brezinsek, S., Bright, M. D. J., Brix, M., Broeckx, W., Brombin, M., Broslawski, A., Brown, D. P. D., Brown, M., Bruno, E., Bucalossi, J., Buch, J., Buchanan, J., Buckley, M. A., Budny, R., Bufferand, H., Bulman, M., Bulmer, N., Bunting, P., Buratti, P., Burckhart, A., Buscarino, A., Busse, A., Butler, N. K., Bykov, I., Byrne, J., Cahyna, P., Calabro, G., Calvo, I., Camenen, Y., Camp, P., Campling, D. C., Cane, J., Cannas, B., Capel, A. J., Card, P. J., Cardinali, A., Carman, P., Carr, M., Carralero, D., Carraro, L., Carvalho, B. B., Carvalho, I., Carvalho, P., Casson, F. J., Castaldo, C., Catarino, N., Caumont, J., Causa, F., Cavazzana, R., Cave-Ayland, K., Cavinato, M., Cecconello, M., Ceccuzzi, S., Cecil, E., Cenedese, A., Cesario, R., Challis, C. D., Chandler, M., Chandra, D., Chang, C. S., Chapman, I. T., Chapman, S. C., Chernyshova, M., Chitarin, G., Ciraolo, G., Ciric, D., Citrin, J., Clairet, F., Clark, E., Clark, M., Clarkson, R., Clatworthy, D., Clements, C., Cleverly, M., Coad, J. P., Coates, P. A., Cobalt, A., Coccorese, V., Cocilovo, V., Coda, S., Coelho, R., Coenen, J. W., Coffey, I., Colas, L., Collins, S., Conka, D., Conroy, S., Conway, N., Coombs, D., Cooper, D., Cooper, S. R., Corradino, C., Corre, Y., Corrigan, G., Cortes, S., Coster, D., Couchman, A. S., Cox, M. P., Craciunescu, T., Cramp, S., Craven, R., Crisanti, F., Croci, G., Croft, D., Crombe, K., Crowe, R., Cruz, N., Cseh, G., Cufar, A., Cullen, A., Curuia, M., Czarnecka, A., Dabirikhah, H., Dalgliesh, P., Dalley, S., Dankowski, J., Darrow, D., Davies, O., Davis, W., Day, C., Day, I. E., De Bock, M., de Castro, A., de la Cal, E., de la Luna, E., De Masi, G., de Pablos, J. L., De Temmerman, G., De Tommasi, G., de Vries, P., Deakin, K., Deane, J., Agostini, F. Degli, Dejarnac, R., Delabie, E., den Harder, N., Dendy, R. O., Denis, J., Denner, P., Devaux, S., Devynck, P., Di Maio, F., Di Siena, A., Di Troia, C., Dinca, P., D'Inca, R., Ding, B., Dittmar, T., Doerk, H., Doerner, R. P., Donne, T., Dorling, S. E., Dormido-Canto, S., Doswon, S., Douai, D., Doyle, P. T., Drenik, A., Drewelow, P., Drews, P., Duckworth, Ph., Dumont, R., Dumortier, P., Dunai, D., Dunne, M., Duran, I., Durodie, F., Dutta, P., Duval, B. P., Dux, R., Dylst, K., Dzysiuk, N., Edappala, P. V., Edmond, J., Edwards, A. M., Edwards, J., Eich, Th., Ekedahl, A., El-Jorf, R., Elsmore, C. G., Enachescu, M., Ericsson, G., Eriksson, F., Eriksson, J., Eriksson, L. G., Esposito, B., Esquembri, S., Esser, H. G., Esteve, D., Evans, B., Evans, G. E., Evison, G., Ewart, G. D., Fagan, D., Faitsch, M., Falie, D., Fanni, A., Fasoli, A., Faustin, J. M., Fawlk, N., Fazendeiro, L., Fedorczak, N., Felton, R. C., Fenton, K., Fernades, A., Fernandes, H., Ferreira, J., Fessey, J. A., Fevrier, O., Ficker, O., Field, A., Fietz, S., Figueiredo, A., Figueiredo, J., Fil, A., Finburg, P., Firdaouss, M., Fischer, U., Fittill, L., Fitzgerald, M., Flammini, D., Flanagan, J., Fleming, C., Flinders, K., Fonnesu, N., Fontdecaba, J. M., Formisano, A., Forsythe, L., Fortuna, L., Fortuna-Zalesna, E., Fortune, M., Foster, S., Franke, T., Franklin, T., Frasca, M., Frassinetti, L., Freisinger, M., Fresa, R., Frigione, D., Fuchs, V., Fuller, D., Futatani, S., Fyvie, J., Gal, K., Galassi, D., Galazka, K., Galdon-Quiroga, J., Gallagher, J., Gallart, D., Galvao, R., Gao, X., Gao, Y., Garcia, J., Garcia-Carrasco, A., Garcia-Munoz, M., Gardarein, J. -L., Garzotti, L., Gaudio, P., Gauthier, E., Gear, D. F., Gee, S. J., Geiger, B., Gelfusa, M., Gerasimov, S., Gervasini, G., Gethins, M., Ghani, Z., Ghate, M., Gherendi, M., Giacalone, J. C., Giacomelli, L., Gibson, C. S., Giegerich, T., Gil, C., Gil, L., Gilligan, S., Gin, D., Giovannozzi, E., Girardo, J. B., Giruzzi, G., Gloeggler, S., Godwin, J., Goff, J., Gohil, P., Goloborod'ko, V., Gomes, R., Goncalves, B., Goniche, M., Goodliffe, M., Goodyear, A., Gorini, G., Gosk, M., Goulding, R., Goussarov, A., Gowland, R., Graham, B., Graham, M. E., Graves, J. P., Grazier, N., Grazier, P., Green, N. R., Greuner, H., Grierson, B., Griph, F. S., Grisolia, C., Grist, D., Groth, M., Grove, R., Grundy, C. N., Grzonka, J., Guard, D., Guerard, C., Guillemaut, C., Guirlet, R., Gurl, C., Utoh, H. H., Hackett, L. J., Hacquin, S., Hagar, A., Hager, R., Hakola, A., Halitovs, M., Hall, S. J., Cook, S. P. Hallworth, Hamlyn-Harris, C., Hammond, K., Harrington, C., Harrison, J., Harting, D., Hasenbeck, F., Hatano, Y., Haupt, T. D. V., Hawes, J., Hawkes, N. C., Hawkins, J., Hawkins, P., Haydon, P. W., Hayter, N., Hazel, S., Heesterman, P. J. L., Heinola, K., Hellesen, C., Hellsten, T., Helou, W., Hemming, O. N., Hender, T. C., Henderson, M., Henderson, S. S., Henriques, R., Hepple, D., Hermon, G., Hertout, P., Hidalgo, C., Highcock, E. G., Hill, M., Hillairet, J., Hillesheim, J., Hillis, D., Hizanidis, K., Hjalmarsson, A., Hobirk, J., Hodille, E., Hogben, C. H. A., Hogeweij, G. M. D., Hollingsworth, A., Hollis, S., Homfray, D. A., Horacek, J., Hornung, G., Horton, A. R., Horton, L. D., Horvath, L., Hotchin, S. P., Hough, M. R., Howarth, P. J., Hubbard, A., Huber, A., Huber, V., Huddleston, T. M., Hughes, M., Huijsmans, G. T. A., Hunter, C. L., Huynh, P., Hynes, A. M., Iglesias, D., Imazawa, N., Imbeaux, F., Imrisek, M., Incelli, M., Innocente, P., Irishkin, M., Ivanova-Stanik, I., Jachmich, S., Jacobsen, A. S., Jacquet, P., Jansons, J., Jardin, A., Jarvinen, A., Jaulmes, F., Jednorog, S., Jenkins, I., Jeong, C., Jepu, I., Joffrin, E., Johnson, R., Johnson, T., Johnston, Jane, Joita, L., Jones, G., Jones, T. T. C., Hoshino, K. K., Kallenbach, A., Kamiya, K., Kaniewski, J., Kantor, A., Kappatou, A., Karhunen, J., Karkinsky, D., Karnowska, I., Kaufman, M., Kaveney, G., Kazakov, Y., Kazantzidis, V., Keeling, D. L., Keenan, T., Keep, J., Kempenaars, M., Kennedy, C., Kenny, D., Kent, J., Kent, O. N., Khilkevich, E., Kim, H. T., Kim, H. S., Kinch, A., King, C., King, D., King, R. F., Kinna, D. J., Kiptily, V., Kirk, A., Kirov, K., Kirschner, A., Kizane, G., Klepper, C., Klix, A., Knight, P., Knipe, S. J., Knott, S., Kobuchi, T., Kocsis, G., Kodeli, I., Kogan, L., Kogut, D., Koivuranta, S., Kominis, Y., Koeppen, M., Kos, B., Koskela, T., Koslowski, H. R., Koubiti, M., Kovari, M., Kowalska-Strzeciwilk, E., Krasilnikov, A., Krasilnikov, V., Krawczyk, N., Kresina, M., Krieger, K., Krivska, A., Kruezi, U., Ksiazek, I., Kukushkin, A., Kundu, A., Kurki-Suonio, T., Kwak, S., Kwiatkowski, R., Kwon, O. J., Laguardia, L., Lahtinen, A., Laing, A., Lam, N., Lambertz, H. T., Lane, C., Lang, P. T., Lanthaler, S., Lapins, J., Lasa, A., Last, J. R., Laszynska, E., Lawless, R., Lawson, A., Lawson, K. D., Lazaros, A., Lazzaro, E., Leddy, J., Lee, S., Lefebvre, X., Leggate, H. J., Lehmann, J., Lehnen, M., Leichtle, D., Leichuer, P., Leipold, F., Lengar, I., Lennholm, M., Lerche, E., Lescinskis, A., Lesnoj, S., Letellier, E., Leyland, M., Leysen, W., Li, L., Liang, Y., Likonen, J., Linke, J., Linsmeier, Ch., Lipschultz, B., Liu, G., Liu, Y., Lo Schiavo, V. P., Loarer, T., Loarte, A., Lobel, R. C., Lomanowski, B., Lomas, P. J., Lonnroth, J., Lopez, J. M., Lopez-Razola, J., Lorenzini, R., Losada, U., Lovell, J. J., Loving, A. B., Lowry, C., Luce, T., Lucock, R. M. A., Lukin, A., Luna, C., Lungaroni, M., Lungu, C. P., Lungu, M., Lunniss, A., Lupelli, I., Lyssoivan, A., Macdonald, N., Macheta, P., Maczewa, K., Magesh, B., Maget, P., Maggi, C., Maier, H., Mailloux, J., Makkonen, T., Makwana, R., Malaquias, A., Malizia, A., Manas, P., Manning, A., Manso, M. E., Mantica, P., Mantsinen, M., Manzanares, A., Maquet, Ph., Marandet, Y., Marcenko, N., Marchetto, C., Marchuk, O., Marinelli, M., Marinucci, M., Markovic, T., Marocco, D., Marot, L., Marren, C. A., Marshal, R., Martin, A., Martin, Y., Martin de Aguilera, A., Martinez, F. J., Martin-Solis, J. R., Martynova, Y., Maruyama, S., Masiello, A., Maslov, M., Matejcik, S., Mattei, M., Matthews, G. F., Maviglia, F., Mayer, M., Mayoral, M. L., May-Smith, T., Mazon, D., Mazzotta, C., McAdams, R., McCarthy, P. J., McClements, K. G., McCormack, O., McCullen, P. A., McDonald, D., McIntosh, S., McKean, R., McKehon, J., Meadows, R. C., Meakins, A., Medina, F., Medland, M., Medley, S., Meigh, S., Meigs, A. G., Meisl, G., Meitner, S., Meneses, L., Menmuir, S., Mergia, K., Merrigan, I. R., Mertens, Ph., Meshchaninov, S., Messiaen, A., Meyer, H., Mianowski, S., Michling, R., Middleton-Gear, D., Miettunen, J., Militello, F., Militello-Asp, E., Miloshevsky, G., Mink, F., Minucci, S., Miyoshi, Y., Mlynar, J., Molina, D., Monakhov, I., Moneti, M., Mooney, R., Moradi, S., Mordijck, S., Moreira, L., Moreno, R., Moro, F., Morris, A. W., Morris, J., Moser, L., Mosher, S., Moulton, D., Murari, A., Muraro, A., Murphy, S., Asakura, N. N., Na, Y. S., Nabais, F., Naish, R., Nakano, T., Nardon, E., Naulin, V., Nave, M. F. F., Nedzelski, I., Nemtsev, G., Nespoli, F., Neto, A., Neu, R., Neverov, V. S., Newman, M., Nicholls, K. J., Nicolas, T., Nielsen, A. H., Nielsen, P., Nilsson, E., Nishijima, D., Noble, C., Nocente, M., Nodwell, D., Nordlund, K., Nordman, H., Nouailletas, R., Nunes, I., Oberkofler, M., Odupitan, T., Ogawa, M. T., O'Gorman, T., Okabayashi, M., Olney, R., Omolayo, O., O'Mullane, M., Ongena, J., Orsitto, F., Orszagh, J., Oswuigwe, B. I., Otin, R., Owen, A., Paccagnella, R., Pace, N., Pacella, D., Packer, L. W., Page, A., Pajuste, E., Palazzo, S., Pamela, S., Panja, S., Papp, P., Paprok, R., Parail, V., Park, M., Diaz, F. Parra, Parsons, M., Pasqualotto, R., Patel, A., Pathak, S., Paton, D., Patten, H., Pau, A., Pawelec, E., Soldan, C. Paz, Peackoc, A., Pearson, I. J., Pehkonen, S. -P., Peluso, E., Penot, C., Pereira, A., Pereira, R., Puglia, P. P. Pereira, von Thun, C. Perez, Peruzzo, S., Peschanyi, S., Peterka, M., Petersson, P., Petravich, G., Petre, A., Petrella, N., Petrzilka, V., Peysson, Y., Pfefferle, D., Philipps, V., Pillon, M., Pintsuk, G., Piovesan, P., Pires dos Reis, A., Piron, L., Pironti, A., Pisano, F., Pitts, R., Pizzo, F., Plyusnin, V., Pomaro, N., Pompilian, O. G., Pool, P. J., Popovichev, S., Porfiri, M. T., Porosnicu, C., Porton, M., Possnert, G., Potzel, S., Powell, T., Pozzi, J., Prajapati, V., Prakash, R., Prestopino, G., Price, D., Price, M., Price, R., Prior, P., Proudfoot, R., Pucella, G., Puglia, P., Puiatti, M. E., Pulley, D., Purahoo, K., Puetterich, Th., Rachlew, E., Rack, M., Ragona, R., Rainford, M. S. J., Rakha, A., Ramogida, G., Ranjan, S., Rapson, C. J., Rasmussen, J. J., Rathod, K., Ratta, G., Ratynskaia, S., Ravera, G., Rayner, C., Rebai, M., Reece, D., Reed, A., Refy, D., Regan, B., Regana, J., Reich, M., Reid, N., Reimold, F., Reinhart, M., Reinke, M., Reiser, D., Rendell, D., Reux, C., Reyes Cortes, S. D. A., Reynolds, S., Riccardo, V., Richardson, N., Riddle, K., Rigamonti, D., Rimini, F. G., Risner, J., Riva, M., Roach, C., Robins, R. J., Robinson, S. A., Robinson, T., Robson, D. W., Roccella, R., Rodionov, R., Rodrigues, P., Rodriguez, J., Rohde, V., Romanelli, F., Romanelli, M., Romanelli, S., Romazanov, J., Rowe, S., Rubel, M., Rubinacci, G., Rubino, G., Ruchko, L., Ruiz, M., Ruset, C., Rzadkiewicz, J., Sabot, R., Safi, E., Sagar, P., Saibene, G., Saint-Laurent, F., Salewski, M., Salmi, A., Salmon, R., Salzedas, F., Samaddar, D., Samm, U., Sandiford, D., Santa, P., Santala, M. I. K., Santos, B., Santucci, A., Sartori, F., Sartori, R., Sauter, O., Scannell, R., Schlummer, T., Schmid, K., Schmidt, V., Schmuck, S., Schneider, M., Schoepf, K., Schworer, D., Scott, S. D., Sergienko, G., Sertoli, M., Shabbir, A., Sharapov, S. E., Shaw, A., Shaw, R., Sheikh, H., Shepherd, A., Shevelev, A., Shumack, A., Sias, G., Sibbald, M., Sieglin, B., Silburn, S., Silva, A., Silva, C., Simmons, P. A., Simpson, J., Simpson-Hutchinson, J., Sinha, A., Sipila, S. K., Sips, A. C. 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D., Thomas, P., Thompson, A., Thompson, C. -A., Thompson, V. K., Thorne, L., Thornton, A., Thrysoe, A. S., Tigwell, P. A., Tipton, N., Tiseanu, I., Tojo, H., Tokitani, M., Tolias, P., Tomes, M., Tonner, P., Towndrow, M., Trimble, P., Tripsky, M., Tsalas, M., Tsavalas, P., Jun, D. Tskhakaya, Turner, I., Turner, M. M., Turnyanskiy, M., Tvalashvili, G., Tyrrell, S. G. J., Uccello, A., Ul-Abidin, Z., Uljanovs, J., Ulyatt, D., Urano, H., Uytdenhouwen, I., Vadgama, A. P., Valcarcel, D., Valentinuzzi, M., Valisa, M., Olivares, P. Vallejos, Valovic, M., Van De Mortel, M., Van Eester, D., Van Renterghem, W., van Rooij, G. J., Varje, J., Varoutis, S., Vartanian, S., Vasava, K., Vasilopoulou, T., Vega, J., Verdoolaege, G., Verhoeven, R., Verona, C., Rinati, G. Verona, Veshchev, E., Vianello, N., Vicente, J., Viezzer, E., Villari, S., Villone, F., Vincenzi, P., Vinyar, I., Viola, B., Vitins, A., Vizvary, Z., Vlad, M., Voitsekhovitch, I., Vondracek, P., Vora, N., Vu, T., Pires de Sa, W. W., Wakeling, B., Waldon, C. W. F., Walkden, N., Walker, M., Walker, R., Walsh, M., Wang, E., Wang, N., Warder, S., Warren, R. J., Waterhouse, J., Watkins, N. W., Watts, C., Wauters, T., Weckmann, A., Weiland, J., Weisen, H., Weiszflog, M., Wellstood, C., West, A. T., Wheatley, M. R., Whetham, S., Whitehead, A. M., Whitehead, B. D., Widdowson, A. M., Wiesen, S., Wilkinson, J., Williams, J., Williams, M., Wilson, A. R., Wilson, D. J., Wilson, H. R., Wilson, J., Wischmeier, M., Withenshaw, G., Withycombe, A., Witts, D. M., Wood, D., Wood, R., Woodley, C., Wray, S., Wright, J., Wright, J. C., Wu, J., Wukitch, S., Wynn, A., Xu, T., Yadikin, D., Yanling, W., Yao, L., Yavorskij, V., Yoo, M. G., Young, C., Young, D., Young, I. D., Young, R., Zacks, J., Zagorski, R., Zaitsev, F. S., Zanino, R., Zarins, A., Zastrow, K. D., Zerbini, M., Zhang, W., Zhou, Y., Zilli, E., Zoita, V., Zoletnik, S., Zychor, I., DIII-D Team, JET Contributors, Department of Physics, and Materials Physics

Subjects
Nuclear and High Energy Physics, Tokamak, FOS: Physical sciences, fingerprint, Electron, shear, 114 Physical sciences, 01 natural sciences, h-mode, 010305 fluids & plasmas, law.invention, kinetic ballooning mode, electron temperature gradient mode, mode edge barrier, law, Physics::Plasma Physics, 0103 physical sciences, 010306 general physics, tokamak, micro tearing mode, Physics, Jet (fluid), Fusion, alfven waves, Mode (statistics), Condensed Matter Physics, Physics - Plasma Physics, Computational physics, stabilization, Plasma Physics (physics.plasm-ph), kinetic-theory, impurity transport, transport, Particle, Electron temperature, Energy (signal processing), pedestal
Abstract

Fusion performance in tokamaks hinges critically on the efficacy of the edge transport barrier (ETB) in suppressing energy losses. The new concept of 'fingerprints' is introduced to identify the instabilities that cause transport losses in the ETBs of many of today's experiments, from among widely posited candidates. Analysis of the gyrokinetic-Maxwell equations and gyrokinetic simulations of experiments reveals that each mode type produces characteristic ratios of transport in the various channels: density, heat, and impurities. This, together with experimental observations of transport in some channel or of the relative size of the driving sources of channels, can identify or determine the dominant modes causing energy transport. In multiple H-mode cases with edge-localized modes that are examined, these fingerprints indicate that magnetohydrodynamic (MHD)-like modes are apparently not the dominant agent of energy transport; rather, this role is played by micro-tearing modes (MTMs) and electron temperature gradient (ETG) modes, and in addition, possibly by ion temperature gradient/ trapped electron modes (ITG/TEM) on JET (Joint European 'Torus). MHD-like modes may dominate the electron particle losses. Fluctuation frequency can also be an important means of identification, and is often closely related to the transport fingerprint. The analytical arguments unify and explain previously disparate experimental observations on multiple devices, including DIII-D, JET, and ASDEX-U. Detailed simulations of two DIII-D ETBs also demonstrate and corroborate this.

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214. A potentially robust plasma profile control approach for ITER using real-time estimation of linearized profile response models

Author

Kim, S. H. and Lister, J. B.

Subjects
Simulations, H-Mode, Tokamak, Jet, Feedback-Control, Tore-Supra, Discharges, Steady-State Scenarios, Diii-D, Hybrid
Abstract

An active plasma profile control approach for ITER, which is potentially robust by being tolerant to changing and uncertain physics, has been explored in this work, using a technique based on real-time estimation of linearized profile response models. The linearized models approximate static responses of the plasma profiles to power changes in auxiliary heating and current drive systems. These models are updated in real-time, differing from the model-based technique which deduces a dynamic model from identification experiments. The underlying physics is simplified with several assumptions to allow real-time update of the profile response models; however, without significant loss of information necessary for feedback control of the plasma profiles. The response of the electron temperature profile is modelled by simplifying the electron heat transport equation. The response of the safety factor profile is computed by directly relating it to the changes in source current density profiles. The required actuator power changes are directly computed by inverting the response matrix using the singular value decomposition technique. The saturation of the actuator powers is taken into account and the capability of using quantized auxiliary powers is provided. The potential of our active control approach has been tested by applying it to simulations of the ITER hybrid mode operation using CRONOS. In these simulations, either a global transport model or a theory-based local transport model has been used and the electron temperature and safety factor profiles were well controlled either independently or simultaneously.

215. High Density Plasma Heating in the Tokamak à Configuration Variable

Author

Curchod, Loïc and Pochelon, Antoine

Subjects
LH, détecteur de rayons-X mous, mode-H, EBH, electron Bernstein waves, PI, génération de courant, chauffage, heating, antenne, ondes cyclotroniques électroniques, electron cyclotron waves, conversion de mode, EBW, parametric instability, lower-hybrid waves, haute densité, tokamak, plasma, DML, mode conversion, power absorption, high density, ECH, DMPX, loop-antenna, plasmas, boucle diamagnétique, diamagnetic loop, H-mode, ECW, absorption de puissance, EBCD, current drive, soft X-ray detector, ondes hybrides inférieures, ECCD, TCV, O-X-B, ondes de Bernstein électroniques, instabilité paramétrique
Abstract

The Tokamak à Configuration Variable (TCV) is a medium size magnetic confinement thermonuclear fusion experiment designed for the study of the plasma performances as a function of its shape. It is equipped with a high power and highly flexible electron cyclotron heating (ECH) and current drive (ECCD) system. Up to 3 MW of 2nd harmonic EC power in ordinary (O2) or extraordinary (X2) polarization can be injected from TCV low-field side via six independently steerable launchers. In addition, up to 1:5 MW of 3rd harmonic EC power (X3) can be launched along the EC resonance from the top of TCV vacuum vessel. At high density, standard ECH and ECCD are prevented by the appearance of a cutoff layer screening the access to the EC resonance at the plasma center. As a consequence, less than 50% of TCV density operational domain is accessible to X2 and X3 ECH. The electron Bernstein waves (EBW) have been proposed to overcome this limitation. EBW is an electrostatic mode propagating beyond the plasma cutoff without upper density limit. Since it cannot propagate in vacuum, it has to be excited by mode conversion of EC waves in the plasma. Efficient electron Bernstein waves heating (EBH) and current drive (EBCD) were previously performed in several fusion devices, in particular in the W7-AS stellarator and in the MAST spherical tokamak. In TCV, the conditions for an efficient O-X-B mode conversion (i.e. a steep density gradient at the O2 plasma cutoff) are met at the edge of high confinement (H-mode) plasmas characterized by the appearance of a pedestal in the electron temperature and density profiles. TCV experiments have demonstrated the first EBW coupling to overdense plasmas in a medium aspect-ratio tokamak via O-X-B mode conversion. This thesis work focuses on several aspects of ECH and EBH in low and high density plasmas. Firstly, the experimental optimum angle for the O-X-B mode conversion is successfully compared to the full-wave mode conversion calculation of the AMR code. The implementation of TCV ECH system geometry in AMR and the coupling of AMR to the LUKE quasi-linear Fokker-Planck solver for the TCV environment were part of this work. The power deposition location of modulated EBH is then detected inside the O2 plasma cutoff by oscillation analysis of the soft X-ray emission profile using the break-in-slope (BIS) analysis and a harmonic response identification method (HRIM), which is the demonstration of resonant EBH in TCV. The BIS and HRIM methods are also used to successfully detect and track the time-varying deposition locations of one and then two X2 power beams simultaneously. All experimental results are in good agreement within 10% of the normalized plasma radius with numerical results of the AMR and C3PO ray-tracing codes coupled to LUKE. The global power absorption coefficient of modulated ECH (MECH) is studied by HRIM analysis of the plasma toroidal flux response measured by TCV diamagnetic loop (DML). Analysis of earlier X3 MECH and new X2 MECH experiments reveals a major perturbation of the method by the sawtooth magnetohydrodynamic activity in the plasma center. Indeed, an asymmetric improvement of the X3 power absorption (up to 100%) with respect to the sign of the X2 ECCD pre-heating was observed in previous TCV experiments and remained unexplained by Fokker-Planck simulations until now. The present work allows to attribute this asymmetry to a sawtooth activity strongly destabilized by the central X2 co-ECCD locking to the X3 power modulation. The performances of EBW current drive (EBCD) in TCV are studied with the AMR-LUKE codes for several poloidal positions of the EBW injection. The maximum EBCD efficiency is obtained when the EBW are injected close the plasma midplane such that the wave parallel refractive index upshift is moderate and the absorption takes place at the plasma center where the electron temperature is the highest. However, the absolute driven current remains small (i.e. ≲1% of the Ohmic current). Finally, a new loop-antenna for the detection of the lower-hybrid (LH) waves generated by a parametric instability (PI) at the X-B mode conversion was designed, built and installed in TCV torus. Fast monitoring of the LHPI spectrum allows to show for the first time the correlation of the amplitude of the detected waves with the local LHPI threshold power at the mode conversion region, estimated from the experimental profiles data. In an EBW power scan, the LHPI threshold power is estimated to be ≲50 kW in good agreement with the value predicted from the experimental profiles data. The LHPI energy cascade from the low to the high LH frequency bands with increasing EBH power is shown for the first time in TCV.

216. Theoretical study of electronic transport in TCV ELMy H-mode

Author

Induni, Gaël and Sauter, Olivier

Subjects
H-mode, ASTRA, Physics::Plasma Physics, MHD, electronic transport, ELM, TCV, simulation
Abstract

High-confinement mode (H-mode) is a promising reference scenario for ITER. But we are still facing major issues because of instabilities. They expel periodically some of the energy, which can damage the device. These instabilities are called the edge localized modes (ELM) and are not yet fully theoretically understood. The present work is a study on the profiles evolution in between ELMs and on the ELM effects. This may help to have a better understanding of the conditions before the ELM. We use the simulations as theoretical tool. For the purpose of the simulations, we build an H-mode χ e profile according to a standard L-mode one that we truncate at the edge to create a transport barrier. This gives a good agreement with the experimental data. Several scaling laws were successfully used. The first one is the energy confinement time scaling which was used for the thermal diffusivity to scale the temperature profile. A scaling between the core and pedestal energies was found recently. It was used to compute the pedestal χ e to scale the temperature pedestal, which was successful. Finally, we used a scaling for transport barriers which links the density gradient length to that of the temperature to compute the density in the pedestal. It was already found to be good in TCV electron internal transport barriers and in ASDEX Upgrade H-mode pedestals. Looking at the MHD stability parameters, it was found that for our reference case, ELMs are not likely to be triggered by the time evolution of the pressure gradient and the current density profiles in our model, as these are only varying significantly during the first millisecond after the crash, and are almost constant during the long remaining time until the next crash. Studying different cases, we investigate the behavior of the plasma when replacing the edge heating by central one to observe the influence of the heating profile, but no significant difference was found, neither in the MHD stability parameters. Further we change the particle diffusion coefficient to compare the dynamic behavior of the density. Slowing down the density dynamic behavior also slows down the pressure one, this can be seen on the MHD stability parameters. We also vary the ELM period to compare to the change due to the variation of the particle diffusivity. It was found that there may be a sort of relation between the particle diffusivity and the ELM period at least for the density, since both cases change the density recovery time with respect to the ELM period. A last case considered is doubling the radial ELM interaction range. This is done in order to observe the difference to the reference simulation that takes the density top of pedestal as ELM range, and to compare the spatial range influenced by the MHD activity and the one by the transport improvement. It was found that the MHD stability parameters in the pedestal exhibit a different behavior with the pressure gradient starting to increase very fast.

217. Analysis of plasma termination in the JET hybrid scenario

Author

Hobirk, J., Bernert, M., Buratti, P., Challis, C. D., Coffey, I, Drewelow, P., Joffrin, E., Mailloux, J., Nunes, I, Pucella, G., Puetterich, T., de Vries, P. C., Abduallev, S., Abhangi, M., Abreu, P., Afzal, M., Aggarwal, K. M., Ahlgren, T., Ahn, J. H., Aho-Mantila, L., Aiba, N., Airila, M., Albanese, R., Aldred, V., Alegre, D., Alessi, E., Aleynikov, P., Alfier, A., Alkseev, A., Allinson, M., Alper, B., Alves, E., Ambrosino, G., Ambrosino, R., Amicucci, L., Amosov, V., Sunden, E. Andersson, Angelone, M., Anghel, M., Angioni, C., Appel, L., Appelbee, C., Arena, P., Ariola, M., Arnichand, H., Arshad, S., Ash, A., Ashikawa, N., Aslanyan, V., Asunta, O., Auriemma, F., Austin, Y., Avotina, L., Axton, M. D., Ayres, C., Bacharis, M., Baciero, A., Baiao, D., Bailey, S., Baker, A., Balboa, I., Balden, M., Balshaw, N., Bament, R., Banks, J. W., Baranov, Y. F., Barnard, M. A., Barnes, D., Barnes, M., Barnsley, R., Wiechec, A. Baron, Orte, L. Barrera, Baruzzo, M., Basiuk, V., Bassan, M., Bastow, R., Batista, A., Batistoni, P., Baughan, R., Bauvir, B., Baylor, L., Bazylev, B., Beal, J., Beaumont, P. S., Beckers, M., Beckett, B., Becoulet, A., Bekris, N., Beldishevski, M., Bell, K., Belli, F., Bellinger, M., Belonohy, E., Ben Ayed, N., Benterman, N. A., Bergsaker, H., Bernardo, J., Berry, M., Bertalot, L., Besliu, C., Beurskens, M., Bieg, B., Bielecki, J., Biewer, T., Bigi, M., Bilkova, P., Binda, F., Bisoffi, A., Bizarro, J. P. S., Bjorkas, C., Blackburn, J., Blackman, K., Blackman, T. R., Blanchard, P., Blatchford, P., Bobkov, V., Boboc, A., Bodnar, G., Bogar, O., Bolshakova, I., Bolzonella, T., Bonanomi, N., Bonelli, F., Boom, J., Booth, J., Borba, D., Borodin, D., Borodkina, I., Botrugno, A., Bottereau, C., Boulting, P., Bourdelle, C., Bowden, M., Bower, C., Bowman, C., Boyce, T., Boyd, C., Boyer, H. J., Bradshaw, J. M. A., Braic, V., Bravanec, R., Breizman, B., Bremond, S., Brennan, P. D., Breton, S., Brett, A., Brezinsek, S., Bright, M. D. J., Brix, M., Broeckx, W., Brombin, M., Broslawski, A., Brown, D. P. D., Brown, M., Bruno, E., Bucalossi, J., Buch, J., Buchanan, J., Buckley, M. A., Budny, R., Bufferand, H., Bulman, M., Bulmer, N., Bunting, P., Burckhart, A., Buscarino, A., Busse, A., Butler, N. K., Bykov, I., Byrne, J., Cahyna, P., Calabro, G., Calvo, I., Camenen, Y., Camp, P., Campling, D. C., Cane, J., Cannas, B., Capel, A. J., Card, P. J., Cardinali, A., Carman, P., Carr, M., Carralero, D., Carraro, L., Carvalho, B. B., Carvalho, I., Carvalho, P., Casson, F. J., Castaldo, C., Catarino, N., Caumont, J., Causa, F., Cavazzana, R., Cave-Ayland, K., Cavinato, M., Cecconello, M., Ceccuzzi, S., Cecil, E., Cenedese, A., Cesario, R., Chandler, M., Chandra, D., Chang, C. S., Chankin, A., Chapman, I. T., Chapman, S. C., Chernyshova, M., Chitarin, G., Ciraolo, G., Ciric, D., Citrin, J., Clairet, F., Clark, E., Clark, M., Clarkson, R., Clatworthy, D., Clements, C., Cleverly, M., Coad, J. P., Coates, P. A., Cobalt, A., Coccorese, V., Cocilovo, V., Coda, S., Coelho, R., Coenen, J. W., Coffey, I., Colas, L., Collins, S., Conka, D., Conroy, S., Conway, N., Coombs, D., Cooper, D., Cooper, S. R., Corradino, C., Corre, Y., Corrigan, G., Cortes, S., Coster, D., Couchman, A. S., Cox, M. P., Craciunescu, T., Cramp, S., Craven, R., Crisanti, F., Croci, G., Croft, D., Crombe, K., Crowe, R., Cruz, N., Cseh, G., Cufar, A., Cullen, A., Curuia, M., Czarnecka, A., Dabirikhah, H., Dalgliesh, P., Dalley, S., Dankowski, J., Darrow, D., Davies, O., Davis, W., Day, C., Day, I. E., De Bock, M., de Castro, A., de la Cal, E., de la Luna, E., De Masi, G., de Pablos, J. L., De Temmerman, G., De Tommasi, G., de Vries, P., Deakin, K., Deane, J., Agostini, F. Degli, Dejarnac, R., Delabie, E., den Harder, N., Dendy, R. O., Denis, J., Denner, P., Devaux, S., Devynck, P., Di Maio, F., Di Siena, A., Di Troia, C., Dinca, P., D'Inca, R., Ding, B., Dittmar, T., Doerk, H., Doerner, R. P., Donne, T., Dorling, S. E., Dormido-Canto, S., Doswon, S., Douai, D., Doyle, P. T., Drenik, A., Drews, P., Duckworth, Ph., Dumont, R., Dumortier, P., Dunai, D., Dunne, M., Duran, I., Durodie, F., Dutta, P., Duval, B. P., Dux, R., Dylst, K., Dzysiuk, N., Edappala, P. V., Edmond, J., Edwards, A. M., Edwards, J., Eich, Th., Ekedahl, A., El-Jorf, R., Elsmore, C. G., Enachescu, M., Ericsson, G., Eriksson, F., Eriksson, J., Eriksson, L. G., Esposito, B., Esquembri, S., Esser, H. G., Esteve, D., Evans, B., Evans, G. E., Evison, G., Ewart, G. D., Fagan, D., Faitsch, M., Falie, D., Fanni, A., Fasoli, A., Faustin, J. M., Fawlk, N., Fazendeiro, L., Fedorczak, N., Felton, R. C., Fenton, K., Fernades, A., Fernandes, H., Ferreira, J., Fessey, J. A., Fevrier, O., Ficker, O., Field, A., Fietz, S., Figueiredo, A., Figueiredo, J., Fil, A., Finburg, P., Firdaouss, M., Fischer, U., Fittill, L., Fitzgerald, M., Flammini, D., Flanagan, J., Fleming, C., Flinders, K., Fonnesu, N., Fontdecaba, J. M., Formisano, A., Forsythe, L., Fortuna, L., Fortuna-Zalesna, E., Fortune, M., Foster, S., Franke, T., Franklin, T., Frasca, M., Frassinetti, L., Freisinger, M., Fresa, R., Frigione, D., Fuchs, V., Fuller, D., Futatani, S., Fyvie, J., Gal, K., Galassi, D., Galazka, K., Galdon-Quiroga, J., Gallagher, J., Gallart, D., Galvao, R., Gao, X., Gao, Y., Garcia, J., Garcia-Carrasco, A., Garcia-Munoz, M., Gardarein, J. -L., Garzotti, L., Gaudio, P., Gauthier, E., Gear, D. F., Gee, S. J., Geiger, B., Gelfusa, M., Gerasimov, S., Gervasini, G., Gethins, M., Ghani, Z., Ghate, M., Gherendi, M., Giacalone, J. C., Giacomelli, L., Gibson, C. S., Giegerich, T., Gil, C., Gil, L., Gilligan, S., Gin, D., Giovannozzi, E., Girardo, J. B., Giroud, C., Giruzzi, G., Gloeggler, S., Godwin, J., Goff, J., Gohil, P., Goloborod'ko, V., Gomes, R., Goncalves, B., Goniche, M., Goodliffe, M., Goodyear, A., Gorini, G., Gosk, M., Goulding, R., Goussarov, A., Gowland, R., Graham, B., Graham, M. E., Graves, J. P., Grazier, N., Grazier, P., Green, N. R., Greuner, H., Grierson, B., Griph, F. S., Grisolia, C., Grist, D., Groth, M., Grove, R., Grundy, C. N., Grzonka, J., Guard, D., Guerard, C., Guillemaut, C., Guirlet, R., Gurl, C., Utoh, H. H., Hackett, L. J., Hacquin, S., Hagar, A., Hager, R., Hakola, A., Halitovs, M., Hall, S. J., Cook, S. P. Hallworth, Hamlyn-Harris, C., Hammond, K., Harrington, C., Harrison, J., Harting, D., Hasenbeck, F., Hatano, Y., Hatch, D. R., Haupt, T. D. V., Hawes, J., Hawkes, N. C., Hawkins, J., Hawkins, P., Haydon, P. W., Hayter, N., Hazel, S., Heesterman, P. J. L., Heinola, K., Hellesen, C., Hellsten, T., Helou, W., Hemming, O. N., Hender, T. C., Henderson, M., Henderson, S. S., Henriques, R., Hepple, D., Hermon, G., Hertout, P., Hidalgo, C., Highcock, E. G., Hill, M., Hillairet, J., Hillesheim, J., Hillis, D., Hizanidis, K., Hjalmarsson, A., Hodille, E., Hogben, C. H. A., Hogeweij, G. M. D., Hollingsworth, A., Hollis, S., Homfray, D. A., Horacek, J., Hornung, G., Horton, A. R., Horton, L. D., Horvath, L., Hotchin, S. P., Hough, M. R., Howarth, P. J., Hubbard, A., Huber, A., Huber, V., Huddleston, T. M., Hughes, M., Huijsmans, G. T. A., Hunter, C. L., Huynh, P., Hynes, A. M., Iglesias, D., Imazawa, N., Imbeaux, F., Imrisek, M., Incelli, M., Innocente, P., Irishkin, M., Ivanova-Stanik, I., Jachmich, S., Jacobsen, A. S., Jacquet, P., Jansons, J., Jardin, A., Jarvinen, A., Jaulmes, F., Jednorog, S., Jenkins, I., Jeong, C., Jepu, I., Johnson, R., Johnson, T., Johnston, Jane, Joita, L., Jones, G., Jones, T. T. C., Hoshino, K. K., Kallenbach, A., Kamiya, K., Kaniewski, J., Kantor, A., Kappatou, A., Karhunen, J., Karkinsky, D., Karnowska, I., Kaufman, M., Kaveney, G., Kazakov, Y., Kazantzidis, V., Keeling, D. L., Keenan, T., Keep, J., Kempenaars, M., Kennedy, C., Kenny, D., Kent, J., Kent, O. N., Khilkevich, E., Kim, H. T., Kim, H. S., Kinch, A., King, C., King, D., King, R. F., Kinna, D. J., Kiptily, V., Kirk, A., Kirov, K., Kirschner, A., Kizane, G., Klepper, C., Klix, A., Knight, P., Knipe, S. J., Knott, S., Kobuchi, T., Koechl, F., Kocsis, G., Kodeli, I., Kogan, L., Kogut, D., Koivuranta, S., Kominis, Y., Koeppen, M., Kos, B., Koskela, T., Koslowski, H. R., Koubiti, M., Kovari, M., Kowalska-Strzeciwilk, E., Krasilnikov, A., Krasilnikov, V., Krawczyk, N., Kresina, M., Krieger, K., Krivska, A., Kruezi, U., Ksiazek, I., Kukushkin, A., Kundu, A., Kurki-Suonio, T., Kwak, S., Kwiatkowski, R., Kwon, O. J., Laguardia, L., Lahtinen, A., Laing, A., Lam, N., Lambertz, H. T., Lane, C., Lang, P. T., Lanthaler, S., Lapins, J., Lasa, A., Last, J. R., Laszynska, E., Lawless, R., Lawson, A., Lawson, K. D., Lazaros, A., Lazzaro, E., Leddy, J., Lee, S., Lefebvre, X., Leggate, H. J., Lehmann, J., Lehnen, M., Leichtle, D., Leichuer, P., Leipold, F., Lengar, I., Lennholm, M., Lerche, E., Lescinskis, A., Lesnoj, S., Letellier, E., Leyland, M., Leysen, W., Li, L., Liang, Y., Likonen, J., Linke, J., Linsmeier, Ch., Lipschultz, B., Liu, G., Liu, Y., Lo Schiavo, V. P., Loarer, T., Loarte, A., Lobel, R. C., Lomanowski, B., Lomas, P. J., Lonnroth, J., Lopez, J. M., Lopez-Razola, J., Lorenzini, R., Losada, U., Lovell, J. J., Loving, A. B., Lowry, C., Luce, T., Lucock, R. M. A., Lukin, A., Luna, C., Lungaroni, M., Lungu, C. P., Lungu, M., Lunniss, A., Lupelli, I., Lyssoivan, A., Macdonald, N., Macheta, P., Maczewa, K., Magesh, B., Maget, P., Maggi, C., Maier, H., Makkonen, T., Makwana, R., Malaquias, A., Malizia, A., Manas, P., Manning, A., Manso, M. E., Mantica, P., Mantsinen, M., Manzanares, A., Maquet, Ph., Marandet, Y., Marcenko, N., Marchetto, C., Marchuk, O., Marinelli, M., Marinucci, M., Markovic, T., Marocco, D., Marot, L., Marren, C. A., Marshal, R., Martin, A., Martin, Y., Martin de Aguilera, A., Martinez, F. J., Martin-Solis, J. R., Martynova, Y., Maruyama, S., Masiello, A., Maslov, M., Matejcik, S., Mattei, M., Matthews, G. F., Maviglia, F., Mayer, M., Mayoral, M. L., May-Smith, T., Mazon, D., Mazzotta, C., McAdams, R., McCarthy, P. J., McClements, K. G., McCormack, O., McCullen, P. A., McDonald, D., McIntosh, S., McKean, R., McKehon, J., Meadows, R. C., Meakins, A., Medina, F., Medland, M., Medley, S., Meigh, S., Meigs, A. G., Meisl, G., Meitner, S., Meneses, L., Menmuir, S., Mergia, K., Merrigan, I. R., Mertens, Ph., Meshchaninov, S., Messiaen, A., Meyer, H., Mianowski, S., Michling, R., Middleton-Gear, D., Miettunen, J., Militello, F., Militello-Asp, E., Miloshevsky, G., Mink, F., Minucci, S., Miyoshi, Y., Mlynar, J., Molina, D., Monakhov, I., Moneti, M., Mooney, R., Moradi, S., Mordijck, S., Moreira, L., Moreno, R., Moro, F., Morris, A. W., Morris, J., Moser, L., Mosher, S., Moulton, D., Murari, A., Muraro, A., Murphy, S., Asakura, N. N., Na, Y. S., Nabais, F., Naish, R., Nakano, T., Nardon, E., Naulin, V., Nave, M. F. F., Nedzelski, I., Nemtsev, G., Nespoli, F., Neto, A., Neu, R., Neverov, V. S., Newman, M., Nicholls, K. J., Nicolas, T., Nielsen, A. H., Nielsen, P., Nilsson, E., Nishijima, D., Noble, C., Nocente, M., Nodwell, D., Nordlund, K., Nordman, H., Nouailletas, R., Nunes, I., Oberkofler, M., Odupitan, T., Ogawa, M. T., O'Gorman, T., Okabayashi, M., Olney, R., Omolayo, O., O'Mullane, M., Ongena, J., Orsitto, F., Orszagh, J., Oswuigwe, B. I., Otin, R., Owen, A., Paccagnella, R., Pace, N., Pacella, D., Packer, L. W., Page, A., Pajuste, E., Palazzo, S., Pamela, S., Panja, S., Papp, P., Paprok, R., Parail, V., Park, M., Diaz, F. Parra, Parsons, M., Pasqualotto, R., Patel, A., Pathak, S., Paton, D., Patten, H., Pau, A., Pawelec, E., Soldan, C. Paz, Peackoc, A., Pearson, I. J., Pehkonen, S. -P., Peluso, E., Penot, C., Pereira, A., Pereira, R., Puglia, P. P. Pereira, von Thun, C. Perez, Peruzzo, S., Peschanyi, S., Peterka, M., Petersson, P., Petravich, G., Petre, A., Petrella, N., Petrzilka, V., Peysson, Y., Pfefferle, D., Philipps, V., Pillon, M., Pintsuk, G., Piovesan, P., Pires dos Reis, A., Piron, L., Pironti, A., Pisano, F., Pitts, R., Pizzo, F., Plyusnin, V., Pomaro, N., Pompilian, O. G., Pool, P. J., Popovichev, S., Porfiri, M. T., Porosnicu, C., Porton, M., Possnert, G., Potzel, S., Powell, T., Pozzi, J., Prajapati, V., Prakash, R., Prestopino, G., Price, D., Price, M., Price, R., Prior, P., Proudfoot, R., Puglia, P., Puiatti, M. E., Pulley, D., Purahoo, K., Puetterich, Th., Rachlew, E., Rack, M., Ragona, R., Rainford, M. S. J., Rakha, A., Ramogida, G., Ranjan, S., Rapson, C. J., Rasmussen, J. J., Rathod, K., Ratta, G., Ratynskaia, S., Ravera, G., Rayner, C., Rebai, M., Reece, D., Reed, A., Refy, D., Regan, B., Regana, J., Reich, M., Reid, N., Reimold, F., Reinhart, M., Reinke, M., Reiser, D., Rendell, D., Reux, C., Reyes Cortes, S. D. A., Reynolds, S., Riccardo, V., Richardson, N., Riddle, K., Rigamonti, D., Rimini, F. G., Risner, J., Riva, M., Roach, C., Robins, R. J., Robinson, S. A., Robinson, T., Robson, D. W., Roccella, R., Rodionov, R., Rodrigues, P., Rodriguez, J., Rohde, V., Romanelli, F., Romanelli, M., Romanelli, S., Romazanov, J., Rowe, S., Rubel, M., Rubinacci, G., Rubino, G., Ruchko, L., Ruiz, M., Ruset, C., Rzadkiewicz, J., Saarelma, S., Sabot, R., Safi, E., Sagar, P., Saibene, G., Saint-Laurent, F., Salewski, M., Salmi, A., Salmon, R., Salzedas, F., Samaddar, D., Samm, U., Sandiford, D., Santa, P., Santala, M. I. K., Santos, B., Santucci, A., Sartori, F., Sartori, R., Sauter, O., Scannell, R., Schlummer, T., Schmid, K., Schmidt, V., Schmuck, S., Schneider, M., Schoepf, K., Schworer, D., Scott, S. D., Sergienko, G., Sertoli, M., Shabbir, A., Sharapov, S. E., Shaw, A., Shaw, R., Sheikh, H., Shepherd, A., Shevelev, A., Shumack, A., Sias, G., Sibbald, M., Sieglin, B., Silburn, S., Silva, A., Silva, C., Simmons, P. A., Simpson, J., Simpson-Hutchinson, J., Sinha, A., Sipila, S. K., Sips, A. C. C., Siren, P., Sirinelli, A., Sjostrand, H., Skiba, M., Skilton, R., Slabkowska, K., Slade, B., Smith, N., Smith, P. G., Smith, R., Smith, T. J., Smithies, M., Snoj, L., Soare, S., Solano, E. R., Somers, A., Sommariva, C., Sonato, P., Sopplesa, A., Sousa, J., Sozzi, C., Spagnolo, S., Spelzini, T., Spineanu, F., Stables, G., Stamatelatos, I., Stamp, M. F., Staniec, P., Stankunas, G., Stan-Sion, C., Stead, M. J., Stefanikova, E., Stepanov, I., Stephen, A. V., Stephen, M., Stevens, A., Stevens, B. D., Strachan, J., Strand, P., Strauss, H. R., Strom, P., Stubbs, G., Studholme, W., Subba, F., Summers, H. P., Svensson, J., Swiderski, L., Szabolics, T., Szawlowski, M., Szepesi, G., Suzuki, T. T., Tal, B., Tala, T., Talbot, A. R., Talebzadeh, S., Taliercio, C., Tamain, P., Tame, C., Tang, W., Tardocchi, M., Taroni, L., Taylor, D., Taylor, K. A., Tegnered, D., Telesca, G., Teplova, N., Terranova, D., Testa, D., Tholerus, E., Thomas, J., Thomas, J. D., Thomas, P., Thompson, A., Thompson, C. -A., Thompson, V. K., Thorne, L., Thornton, A., Thrysoe, A. S., Tigwell, P. A., Tipton, N., Tiseanu, I., Tojo, H., Tokitani, M., Tolias, P., Tomes, M., Tonner, P., Towndrow, M., Trimble, P., Tripsky, M., Tsalas, M., Tsavalas, P., Jun, D. Tskhakaya, Turner, I., Turner, M. M., Turnyanskiy, M., Tvalashvili, G., Tyrrell, S. G. J., Uccello, A., Ul-Abidin, Z., Uljanovs, J., Ulyatt, D., Urano, H., Uytdenhouwen, I., Vadgama, A. P., Valcarcel, D., Valentinuzzi, M., Valisa, M., Olivares, P. Vallejos, Valovic, M., Van De Mortel, M., Van Eester, D., Van Renterghem, W., van Rooij, G. J., Varje, J., Varoutis, S., Vartanian, S., Vasava, K., Vasilopoulou, T., Vega, J., Verdoolaege, G., Verhoeven, R., Verona, C., Rinati, G. Verona, Veshchev, E., Vianello, N., Vicente, J., Viezzer, E., Villari, S., Villone, F., Vincenzi, P., Vinyar, I., Viola, B., Vitins, A., Vizvary, Z., Vlad, M., Voitsekhovitch, I., Vondracek, P., Vora, N., Vu, T., Pires de Sa, W. W., Wakeling, B., Waldon, C. W. F., Walkden, N., Walker, M., Walker, R., Walsh, M., Wang, E., Wang, N., Warder, S., Warren, R. J., Waterhouse, J., Watkins, N. W., Watts, C., Wauters, T., Weckmann, A., Weiland, J., Weisen, H., Weiszflog, M., Wellstood, C., West, A. T., Wheatley, M. R., Whetham, S., Whitehead, A. M., Whitehead, B. D., Widdowson, A. M., Wiesen, S., Wilkinson, J., Williams, J., Williams, M., Wilson, A. R., Wilson, D. J., Wilson, H. R., Wilson, J., Wischmeier, M., Withenshaw, G., Withycombe, A., Witts, D. M., Wood, D., Wood, R., Woodley, C., Wray, S., Wright, J., Wright, J. C., Wu, J., Wukitch, S., Wynn, A., Xu, T., Yadikin, D., Yanling, W., Yao, L., Yavorskij, V., Yoo, M. G., Young, C., Young, D., Young, I. D., Young, R., Zacks, J., Zagorski, R., Zaitsev, F. S., Zanino, R., Zarins, A., Zastrow, K. D., Zerbini, M., Zhang, W., Zhou, Y., Zilli, E., Zoita, V., Zoletnik, S., and Zychor, I.

Subjects
termination, magnetic fusion, iter, hybrid scenario, internal transport barrier, asdex upgrade, discharges, disruptions, h-mode, performance
Abstract

This paper analyses the final phase of hybrid scenario discharges at JET, the reduction of auxiliary heating towards finally the Ohmic phase. The here considered Ohmic phase is mostly still in the current flattop but may also be in the current ramp down. For this purpose a database is created of 54 parameters in 7 phases distributed in time of the discharge. It is found that the occurrence of a locked mode is in most cases preceded by a radiation peaking after the main heating phase either in a low power phase and/or in the Ohmic phase. To gain insight on the importance of different parameters in this process a correlation analysis to the radiation peaking in the Ohmic phase is done. The first finding is that the further away in time the analysed phases are the less the correlation is. This means in the end that a good termination scenario might also be able to terminate unhealthy plasmas safely. The second finding is that remaining impurities in the plasma after reducing the heating power in the termination phase are the most important reason for generating a locked mode which can lead to a disruption.

218. Extremely Shaped Plasmas to Improve the Tokamak Concept

Author

Piras, Francesco, Moret, Jean-Marc, and Martin, Yves

Subjects
breakdown, plasma physics, magnetic diagnostics, error field, calibration, edge physics, snowflake, doublet, H-mode, ELM, TCV, tokamak, control, nuclear fusion
Abstract

Energy is essential for human existence and our future depends on plentiful and accessible sources of energy. The world population is fast growing and the average energy used per capita increases. One of the greatest challenges for human beings is that of meeting the growing demand for energy in a responsible, equitable and sustainable way. The possibility to obtain energy by "fusing" light atoms addresses these needs. Nuclear fusion reactions are clean, safe and the amount of fuel present on Earth (hydrogen isotopes) is practically inexhaustible and well distributed. Nuclear fusion is a natural process that occurs in all active stars like our Sun. Since the first demonstration of a deuterium fusion reaction (Rutherford 1933), researchers worldwide have tried to replicate this process on Earth by building a thermonuclear fusion reactor. Nevertheless, the challenge posed by the construction of a nuclear fusion reactor is greater than the one presented earlier by the development of a fission reactor. During the IAEA Conference in Geneva in the early 1958, L.A.Artsimovich declared: "Plasma physics is very difficult. Worldwide collaboration is needed for progress" and E.Teller, at the same conference: "Fusion technology is very complex. It is almost impossible to build a fusion reactor in this century". They were right. The extremely high temperature and density necessary to fuse hydrogen isotopes makes it difficult indeed to create a successful fusion reactor. Even though the physics of the fusion reaction appears clear, we are still facing problems on the road towards bulding the "box" that can efficiently confine the hot gas in the state of plasma. The best results so far have been obtained confining a plasma with strong magnetic fields in a toroidal configuration ("tokamak"). The Centre de Recherches en Physique des Plasmas in Switzerland actively studies this promising configuration towards the development of a nuclear fusion reactor. The experimental activity of the Tokamak à Configuration Variable (TCV) mainly focuses on the research of optimized plasma shapes capable of improving the global performance and solve the technological challenges of a tokamak reactor. Several theoretical and experimental results show the importance of the plasma shape in tokamaks. The maximum value of β (an indicator of the confinement efficiency) is for example related to the ratio between the height and the width of the plasma. The plasma shape can also affect the power necessary to access improved confinement regimes, as well as the plasma stability. This thesis reports on a contribution towards the optimization of the tokamak plasma shape. In particular, it describes the theoretical and experimental studies carried out in the TCV tokamak on two innovative plasma shapes: the doublet shaped plasma and the snowflake divertor. Doublet shaped plasmas have been studied in the past by the General Atomics group. Since then, the development of new plasma diagnostics and the discovery of new confinement regimes have given new reasons for interest in this unusual configuration. TCV is the only tokamak worldwide theoretically able to establish and control this configuration. This thesis illustrates new motivations for creating doublet plasmas. The vertical stability of the configuration is studied using a rigid model and the results are compared with those obtained with the KINX MHD stability code. The best strategy for controlling a doublet on TCV is also investigated, and a possible setup of the TCV control system is suggested for the doublet configuration. Analyzing the possible scenarios for doublet creation, the most promising scenario consists of the creation of two independent plasmas, which are subsequently merged to establish a doublet. For this reason, particular attention needs to be devoted to the problem of the plasma start-up. In this thesis, a general analysis of the TCV ohmic and assisted with ECH plasma start-up is presented, and recent attempts to create a doublet plasma are reported. Since the magnetic field reconstruction at the breakdown time is important to better diagnose these plasmas, the entire magnetic system of TCV has been calibrated with an original technique, also described in the manuscript. The last part of this thesis is devoted to the snowflake divertor configuration. This innovative plasma shape has been proposed and theoretically studied by Dr. D.D.Ryutov from the Lawrence Livermore National Laboratory. In Ryutov's articles, this configuration was proposed to alleviate the problems of the plasma-wall interaction and possibly affect the plasma edge stability. The TCV tokamak was the first to report the creation and control of a snowflake configuration, and the candidate was the principal investigator of this work. These results are accordingly discussed in this thesis. Details are provided in particular on the strategy used to establish the configuration. An edge-localized mode (ELM) H-mode regime, supported by electron cyclotron heating, has been successfully established in a snowflake. This regime exhibits 2 to 3 times lower ELM frequency but only a 20%-30% increase in normalized ELM energy (ΔWELM/WP ) compared to an identically-shaped, conventional, single-null, diverted H-mode. Enhanced stability of mid- to high-toroidal-mode-number ideal modes is consistent with the different snowflake ELM phenomenology. Finally, the capability of the snowflake to redistribute the edge power on the additional strike points has been confirmed experimentally and is also reported in this thesis.

219. Experimental validation of an analytical kinetic model for edge-localized modes in JET-ITER-like wall

Author

Guillemaut, C., Metzger, C., Moulton, D., Heinola, K., O'Mullane, M., Balboa, I., Boom, J., Matthews, G. F., Silburn, S., Solano, E. R., Abduallev, S., Abhangi, M., Abreu, P., Afzal, M., Aggarwal, K. M., Ahlgren, T., Ahn, J. H., Aho-Mantila, L., Aiba, N., Airila, M., Albanese, R., Aldred, V., Alegre, D., Alessi, E., Aleynikov, P., Alfier, A., Alkseev, A., Allinson, M., Alper, B., Alves, E., Ambrosino, G., Ambrosino, R., Amicucci, L., Amosov, V., Sunden, E. Andersson, Angelone, M., Anghel, M., Angioni, C., Appel, L., Appelbee, C., Arena, P., Ariola, M., Arnichand, H., Arshad, S., Ash, A., Ashikawa, N., Aslanyan, V., Asunta, O., Auriemma, F., Austin, Y., Avotina, L., Axton, M. D., Ayres, C., Bacharis, M., Baciero, A., Baiao, D., Bailey, S., Baker, A., Balden, M., Balshaw, N., Bament, R., Banks, J. W., Baranov, Y. F., Barnard, M. A., Barnes, D., Barnes, M., Barnsley, R., Wiechec, A. Baron, Orte, L. Barrera, Baruzzo, M., Basiuk, V., Bassan, M., Bastow, R., Batista, A., Batistoni, P., Baughan, R., Bauvir, B., Baylor, L., Bazylev, B., Beal, J., Beaumont, P. S., Beckers, M., Beckett, B., Becoulet, A., Bekris, N., Beldishevski, M., Bell, K., Belli, F., Bellinger, M., Belonohy, E., Ben Ayed, N., Benterman, N. A., Bergsaker, H., Bernardo, J., Bernert, M., Berry, M., Bertalot, L., Besliu, C., Beurskens, M., Bieg, B., Bielecki, J., Biewer, T., Bigi, M., Bilkova, P., Binda, F., Bisoffi, A., Bizarro, J. P. S., Bjorkas, C., Blackburn, J., Blackman, K., Blackman, T. R., Blanchard, P., Blatchford, P., Bobkov, V., Boboc, A., Bodnar, G., Bogar, O., Bolshakova, I., Bolzonella, T., Bonanomi, N., Bonelli, F., Booth, J., Borba, D., Borodin, D., Borodkina, I., Botrugno, A., Bottereau, C., Boulting, P., Bourdelle, C., Bowden, M., Bower, C., Bowman, C., Boyce, T., Boyd, C., Boyer, H. J., Bradshaw, J. M. A., Braic, V., Bravanec, R., Breizman, B., Bremond, S., Brennan, P. D., Breton, S., Brett, A., Brezinsek, S., Bright, M. D. J., Brix, M., Broeckx, W., Brombin, M., Broslawski, A., Brown, D. P. D., Brown, M., Bruno, E., Bucalossi, J., Buch, J., Buchanan, J., Buckley, M. A., Budny, R., Bufferand, H., Bulman, M., Bulmer, N., Bunting, P., Buratti, P., Burckhart, A., Buscarino, A., Busse, A., Butler, N. K., Bykov, I., Byrne, J., Cahyna, P., Calabro, G., Calvo, I., Camenen, Y., Camp, P., Campling, D. C., Cane, J., Cannas, B., Capel, A. J., Card, P. J., Cardinali, A., Carman, P., Carr, M., Carralero, D., Carraro, L., Carvalho, B. B., Carvalho, I., Carvalho, P., Casson, F. J., Castaldo, C., Catarino, N., Caumont, J., Causa, F., Cavazzana, R., Cave-Ayland, K., Cavinato, M., Cecconello, M., Ceccuzzi, S., Cecil, E., Cenedese, A., Cesario, R., Challis, C. D., Chandler, M., Chandra, D., Chang, C. S., Chankin, A., Chapman, I. T., Chapman, S. C., Chernyshova, M., Chitarin, G., Ciraolo, G., Ciric, D., Citrin, J., Clairet, F., Clark, E., Clark, M., Clarkson, R., Clatworthy, D., Clements, C., Cleverly, M., Coad, J. P., Coates, P. A., Cobalt, A., Coccorese, V., Cocilovo, V., Coda, S., Coelho, R., Coenen, J. W., Coffey, I., Colas, L., Collins, S., Conka, D., Conroy, S., Conway, N., Coombs, D., Cooper, D., Cooper, S. R., Corradino, C., Corre, Y., Corrigan, G., Cortes, S., Coster, D., Couchman, A. S., Cox, M. P., Craciunescu, T., Cramp, S., Craven, R., Crisanti, F., Croci, G., Croft, D., Crombe, K., Crowe, R., Cruz, N., Cseh, G., Cufar, A., Cullen, A., Curuia, M., Czarnecka, A., Dabirikhah, H., Dalgliesh, P., Dalley, S., Dankowski, J., Darrow, D., Davies, O., Davis, W., Day, C., Day, I. E., De Bock, M., de Castro, A., de la Cal, E., de la Luna, E., De Masi, G., de Pablos, J. L., De Temmerman, G., De Tommasi, G., de Vries, P., Deakin, K., Deane, J., Agostini, F. Degli, Dejarnac, R., Delabie, E., den Harder, N., Dendy, R. O., Denis, J., Denner, P., Devaux, S., Devynck, P., Di Maio, F., Di Siena, A., Di Troia, C., Dinca, P., D'Inca, R., Ding, B., Dittmar, T., Doerk, H., Doerner, R. P., Donne, T., Dorling, S. E., Dormido-Canto, S., Doswon, S., Douai, D., Doyle, P. T., Drenik, A., Drewelow, P., Drews, P., Duckworth, Ph., Dumont, R., Dumortier, P., Dunai, D., Dunne, M., Duran, I., Durodie, F., Dutta, P., Duval, B. P., Dux, R., Dylst, K., Dzysiuk, N., Edappala, P. V., Edmond, J., Edwards, A. M., Edwards, J., Eich, Th., Ekedahl, A., El-Jorf, R., Elsmore, C. G., Enachescu, M., Ericsson, G., Eriksson, F., Eriksson, J., Eriksson, L. G., Esposito, B., Esquembri, S., Esser, H. G., Esteve, D., Evans, B., Evans, G. E., Evison, G., Ewart, G. D., Fagan, D., Faitsch, M., Falie, D., Fanni, A., Fasoli, A., Faustin, J. M., Fawlk, N., Fazendeiro, L., Fedorczak, N., Felton, R. C., Fenton, K., Fernades, A., Fernandes, H., Ferreira, J., Fessey, J. A., Fevrier, O., Ficker, O., Field, A., Fietz, S., Figueiredo, A., Figueiredo, J., Fil, A., Finburg, P., Firdaouss, M., Fischer, U., Fittill, L., Fitzgerald, M., Flammini, D., Flanagan, J., Fleming, C., Flinders, K., Fonnesu, N., Fontdecaba, J. M., Formisano, A., Forsythe, L., Fortuna, L., Fortuna-Zalesna, E., Fortune, M., Foster, S., Franke, T., Franklin, T., Frasca, M., Frassinetti, L., Freisinger, M., Fresa, R., Frigione, D., Fuchs, V., Fuller, D., Futatani, S., Fyvie, J., Gal, K., Galassi, D., Galazka, K., Galdon-Quiroga, J., Gallagher, J., Gallart, D., Galvao, R., Gao, X., Gao, Y., Garcia, J., Garcia-Carrasco, A., Garcia-Munoz, M., Gardarein, J. -L., Garzotti, L., Gaudio, P., Gauthier, E., Gear, D. F., Gee, S. J., Geiger, B., Gelfusa, M., Gerasimov, S., Gervasini, G., Gethins, M., Ghani, Z., Ghate, M., Gherendi, M., Giacalone, J. C., Giacomelli, L., Gibson, C. S., Giegerich, T., Gil, C., Gil, L., Gilligan, S., Gin, D., Giovannozzi, E., Girardo, J. B., Giroud, C., Giruzzi, G., Gloeggler, S., Godwin, J., Goff, J., Gohil, P., Goloborod'ko, V., Gomes, R., Goncalves, B., Goniche, M., Goodliffe, M., Goodyear, A., Gorini, G., Gosk, M., Goulding, R., Goussarov, A., Gowland, R., Graham, B., Graham, M. E., Graves, J. P., Grazier, N., Grazier, P., Green, N. R., Greuner, H., Grierson, B., Griph, F. S., Grisolia, C., Grist, D., Groth, M., Grove, R., Grundy, C. N., Grzonka, J., Guard, D., Guerard, C., Guirlet, R., Gurl, C., Utoh, H. H., Hackett, L. J., Hacquin, S., Hagar, A., Hager, R., Hakola, A., Halitovs, M., Hall, S. J., Cook, S. P. Hallworth, Hamlyn-Harris, C., Hammond, K., Harrington, C., Harrison, J., Harting, D., Hasenbeck, F., Hatano, Y., Hatch, D. R., Haupt, T. D. V., Hawes, J., Hawkes, N. C., Hawkins, J., Hawkins, P., Haydon, P. W., Hayter, N., Hazel, S., Heesterman, P. J. L., Hellesen, C., Hellsten, T., Helou, W., Hemming, O. N., Hender, T. C., Henderson, M., Henderson, S. S., Henriques, R., Hepple, D., Hermon, G., Hertout, P., Hidalgo, C., Highcock, E. G., Hill, M., Hillairet, J., Hillesheim, J., Hillis, D., Hizanidis, K., Hjalmarsson, A., Hobirk, J., Hodille, E., Hogben, C. H. A., Hogeweij, G. M. D., Hollingsworth, A., Hollis, S., Homfray, D. A., Horacek, J., Hornung, G., Horton, A. R., Horton, L. D., Horvath, L., Hotchin, S. P., Hough, M. R., Howarth, P. J., Hubbard, A., Huber, A., Huber, V., Huddleston, T. M., Hughes, M., Huijsmans, G. T. A., Hunter, C. L., Huynh, P., Hynes, A. M., Iglesias, D., Imazawa, N., Imbeaux, F., Imrisek, M., Incelli, M., Innocente, P., Irishkin, M., Ivanova-Stanik, I., Jachmich, S., Jacobsen, A. S., Jacquet, P., Jansons, J., Jardin, A., Jarvinen, A., Jaulmes, F., Jednorog, S., Jenkins, I., Jeong, C., Jepu, I., Joffrin, E., Johnson, R., Johnson, T., Johnston, Jane, Joita, L., Jones, G., Jones, T. T. C., Hoshino, K. K., Kallenbach, A., Kamiya, K., Kaniewski, J., Kantor, A., Kappatou, A., Karhunen, J., Karkinsky, D., Karnowska, I., Kaufman, M., Kaveney, G., Kazakov, Y., Kazantzidis, V., Keeling, D. L., Keenan, T., Keep, J., Kempenaars, M., Kennedy, C., Kenny, D., Kent, J., Kent, O. N., Khilkevich, E., Kim, H. T., Kim, H. S., Kinch, A., King, C., King, D., King, R. F., Kinna, D. J., Kiptily, V., Kirk, A., Kirov, K., Kirschner, A., Kizane, G., Klepper, C., Klix, A., Knight, P., Knipe, S. J., Knott, S., Kobuchi, T., Koechl, F., Kocsis, G., Kodeli, I., Kogan, L., Kogut, D., Koivuranta, S., Kominis, Y., Koeppen, M., Kos, B., Koskela, T., Koslowski, H. R., Koubiti, M., Kovari, M., Kowalska-Strzeciwilk, E., Krasilnikov, A., Krasilnikov, V., Krawczyk, N., Kresina, M., Krieger, K., Krivska, A., Kruezi, U., Ksiazek, I., Kukushkin, A., Kundu, A., Kurki-Suonio, T., Kwak, S., Kwiatkowski, R., Kwon, O. J., Laguardia, L., Lahtinen, A., Laing, A., Lam, N., Lambertz, H. T., Lane, C., Lang, P. T., Lanthaler, S., Lapins, J., Lasa, A., Last, J. R., Laszynska, E., Lawless, R., Lawson, A., Lawson, K. D., Lazaros, A., Lazzaro, E., Leddy, J., Lee, S., Lefebvre, X., Leggate, H. J., Lehmann, J., Lehnen, M., Leichtle, D., Leichuer, P., Leipold, F., Lengar, I., Lennholm, M., Lerche, E., Lescinskis, A., Lesnoj, S., Letellier, E., Leyland, M., Leysen, W., Li, L., Liang, Y., Likonen, J., Linke, J., Linsmeier, Ch., Lipschultz, B., Liu, G., Liu, Y., Lo Schiavo, V. P., Loarer, T., Loarte, A., Lobel, R. C., Lomanowski, B., Lomas, P. J., Lonnroth, J., Lopez, J. M., Lopez-Razola, J., Lorenzini, R., Losada, U., Lovell, J. J., Loving, A. B., Lowry, C., Luce, T., Lucock, R. M. A., Lukin, A., Luna, C., Lungaroni, M., Lungu, C. P., Lungu, M., Lunniss, A., Lupelli, I., Lyssoivan, A., Macdonald, N., Macheta, P., Maczewa, K., Magesh, B., Maget, P., Maggi, C., Maier, H., Mailloux, J., Makkonen, T., Makwana, R., Malaquias, A., Malizia, A., Manas, P., Manning, A., Manso, M. E., Mantica, P., Mantsinen, M., Manzanares, A., Maquet, Ph., Marandet, Y., Marcenko, N., Marchetto, C., Marchuk, O., Marinelli, M., Marinucci, M., Markovic, T., Marocco, D., Marot, L., Marren, C. A., Marshal, R., Martin, A., Martin, Y., Martin de Aguilera, A., Martinez, F. J., Martin-Solis, J. R., Martynova, Y., Maruyama, S., Masiello, A., Maslov, M., Matejcik, S., Mattei, M., Maviglia, F., Mayer, M., Mayoral, M. L., May-Smith, T., Mazon, D., Mazzotta, C., McAdams, R., McCarthy, P. J., McClements, K. G., McCormack, O., McCullen, P. A., McDonald, D., McIntosh, S., McKean, R., McKehon, J., Meadows, R. C., Meakins, A., Medina, F., Medland, M., Medley, S., Meigh, S., Meigs, A. G., Meisl, G., Meitner, S., Meneses, L., Menmuir, S., Mergia, K., Merrigan, I. R., Mertens, Ph., Meshchaninov, S., Messiaen, A., Meyer, H., Mianowski, S., Michling, R., Middleton-Gear, D., Miettunen, J., Militello, F., Militello-Asp, E., Miloshevsky, G., Mink, F., Minucci, S., Miyoshi, Y., Mlynar, J., Molina, D., Monakhov, I., Moneti, M., Mooney, R., Moradi, S., Mordijck, S., Moreira, L., Moreno, R., Moro, F., Morris, A. W., Morris, J., Moser, L., Mosher, S., Murari, A., Muraro, A., Murphy, S., Asakura, N. N., Na, Y. S., Nabais, F., Naish, R., Nakano, T., Nardon, E., Naulin, V., Nave, M. F. F., Nedzelski, I., Nemtsev, G., Nespoli, F., Neto, A., Neu, R., Neverov, V. S., Newman, M., Nicholls, K. J., Nicolas, T., Nielsen, A. H., Nielsen, P., Nilsson, E., Nishijima, D., Noble, C., Nocente, M., Nodwell, D., Nordlund, K., Nordman, H., Nouailletas, R., Nunes, I., Oberkofler, M., Odupitan, T., Ogawa, M. T., O'Gorman, T., Okabayashi, M., Olney, R., Omolayo, O., Ongena, J., Orsitto, F., Orszagh, J., Oswuigwe, B. I., Otin, R., Owen, A., Paccagnella, R., Pace, N., Pacella, D., Packer, L. W., Page, A., Pajuste, E., Palazzo, S., Pamela, S., Panja, S., Papp, P., Paprok, R., Parail, V., Park, M., Diaz, F. Parra, Parsons, M., Pasqualotto, R., Patel, A., Pathak, S., Paton, D., Patten, H., Pau, A., Pawelec, E., Soldan, C. Paz, Peackoc, A., Pearson, I. J., Pehkonen, S. -P., Peluso, E., Penot, C., Pereira, A., Pereira, R., Puglia, P. P. Pereira, von Thun, C. Perez, Peruzzo, S., Peschanyi, S., Peterka, M., Petersson, P., Petravich, G., Petre, A., Petrella, N., Petrzilka, V., Peysson, Y., Pfefferle, D., Philipps, V., Pillon, M., Pintsuk, G., Piovesan, P., Pires dos Reis, A., Piron, L., Pironti, A., Pisano, F., Pitts, R., Pizzo, F., Plyusnin, V., Pomaro, N., Pompilian, O. G., Pool, P. J., Popovichev, S., Porfiri, M. T., Porosnicu, C., Porton, M., Possnert, G., Potzel, S., Powell, T., Pozzi, J., Prajapati, V., Prakash, R., Prestopino, G., Price, D., Price, M., Price, R., Prior, P., Proudfoot, R., Pucella, G., Puglia, P., Puiatti, M. E., Pulley, D., Purahoo, K., Puetterich, Th., Rachlew, E., Rack, M., Ragona, R., Rainford, M. S. J., Rakha, A., Ramogida, G., Ranjan, S., Rapson, C. J., Rasmussen, J. J., Rathod, K., Ratta, G., Ratynskaia, S., Ravera, G., Rayner, C., Rebai, M., Reece, D., Reed, A., Refy, D., Regan, B., Regana, J., Reich, M., Reid, N., Reimold, F., Reinhart, M., Reinke, M., Reiser, D., Rendell, D., Reux, C., Reyes Cortes, S. D. A., Reynolds, S., Riccardo, V., Richardson, N., Riddle, K., Rigamonti, D., Rimini, F. G., Risner, J., Riva, M., Roach, C., Robins, R. J., Robinson, S. A., Robinson, T., Robson, D. W., Roccella, R., Rodionov, R., Rodrigues, P., Rodriguez, J., Rohde, V., Romanelli, F., Romanelli, M., Romanelli, S., Romazanov, J., Rowe, S., Rubel, M., Rubinacci, G., Rubino, G., Ruchko, L., Ruiz, M., Ruset, C., Rzadkiewicz, J., Saarelma, S., Sabot, R., Safi, E., Sagar, P., Saibene, G., Saint-Laurent, F., Salewski, M., Salmi, A., Salmon, R., Salzedas, F., Samaddar, D., Samm, U., Sandiford, D., Santa, P., Santala, M. I. K., Santos, B., Santucci, A., Sartori, F., Sartori, R., Sauter, O., Scannell, R., Schlummer, T., Schmid, K., Schmidt, V., Schmuck, S., Schneider, M., Schoepf, K., Schworer, D., Scott, S. D., Sergienko, G., Sertoli, M., Shabbir, A., Sharapov, S. E., Shaw, A., Shaw, R., Sheikh, H., Shepherd, A., Shevelev, A., Shumack, A., Sias, G., Sibbald, M., Sieglin, B., Silva, A., Silva, C., Simmons, P. A., Simpson, J., Simpson-Hutchinson, J., Sinha, A., Sipila, S. K., Sips, A. C. C., Siren, P., Sirinelli, A., Sjostrand, H., Skiba, M., Skilton, R., Slabkowska, K., Slade, B., Smith, N., Smith, P. G., Smith, R., Smith, T. J., Smithies, M., Snoj, L., Soare, S., Somers, A., Sommariva, C., Sonato, P., Sopplesa, A., Sousa, J., Sozzi, C., Spagnolo, S., Spelzini, T., Spineanu, F., Stables, G., Stamatelatos, I., Stamp, M. F., Staniec, P., Stankunas, G., Stan-Sion, C., Stead, M. J., Stefanikova, E., Stepanov, I., Stephen, A. V., Stephen, M., Stevens, A., Stevens, B. D., Strachan, J., Strand, P., Strauss, H. R., Strom, P., Stubbs, G., Studholme, W., Subba, F., Summers, H. P., Svensson, J., Swiderski, L., Szabolics, T., Szawlowski, M., Szepesi, G., Suzuki, T. T., Tal, B., Tala, T., Talbot, A. R., Talebzadeh, S., Taliercio, C., Tamain, P., Tame, C., Tang, W., Tardocchi, M., Taroni, L., Taylor, D., Taylor, K. A., Tegnered, D., Telesca, G., Teplova, N., Terranova, D., Testa, D., Tholerus, E., Thomas, J., Thomas, J. D., Thomas, P., Thompson, A., Thompson, C. -A., Thompson, V. 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Subjects
magnetic confinement fusion, Physics::Plasma Physics, plasma physics, edge-localized modes, edge physics, plasma-wall interaction, h-mode, jet-ilw
Abstract

The design and operation of future fusion devices relying on H-mode plasmas requires reliable modelling of edge-localized modes (ELMs) for precise prediction of divertor target conditions. An extensive experimental validation of simple analytical predictions of the time evolution of target plasma loads during ELMs has been carried out here in more than 70 JET-ITER-like wall H-mode experiments with a wide range of conditions. Comparisons of these analytical predictions with diagnostic measurements of target ion flux density, power density, impact energy and electron temperature during ELMs are presented in this paper and show excellent agreement. The analytical predictions tested here are made with the 'free-streaming' kinetic model (FSM) which describes ELMs as a quasi-neutral plasma bunch expanding along the magnetic field lines into the Scrape-Off Layer without collisions. Consequences of the FSM on energy reflection and deposition on divertor targets during ELMs are also discussed.

220. Axisymmetric oscillations at L-H transitions in JET: M-mode

Author

Solano, Emilia R., Vianello, N., Delabie, E., Hillesheim, J. C., Buratti, P., Refy, D., Balboa, I., Boboc, A., Coelho, R., Sieglin, B., Silburn, S., Drewelow, P., Devaux, S., Dodt, D., Figueiredo, A., Frassinetti, L., Marsen, S., Meneses, L., Maggi, C. F., Morris, J., Gerasimov, S., Baruzzo, M., Stamp, M., Grist, D., Nunes, I., Rimini, F., Schmuck, S., Lupelli, I., Silva, C., and JET Contributors

Subjects
H-mode, Physics::Plasma Physics, MHD, L-H transition, pedestal
Abstract

L to H transition studies at JET have revealed an n = 0, m = 1 magnetic oscillation starting immediately at the L to H transition (called M-mode for brevity). While the magnetic oscillation is present a weak ELM-less H-mode regime is obtained, with a clear increase of density and a weak electron temperature pedestal. It is an intermediate state between L and H-mode. In ICRH heated plasmas or low density NBI plasmas the magnetic mode and the pedestal can remain steady (with small oscillations) for the duration of the heating phase, of order 10 s or more. The axisymmetric magnetic oscillation has period similar to 0.5-2 ms, and poloidal mode number m = 1: it looks like a pedestal localised up/down oscillation, although it is clearly a natural oscillation of the plasma, not driven by the position control system. Electron cyclotron emission, interferometry, reflectometry and fast Li beam measurements locate the mode in the pedestal region. Da, fast infrared camera and Langmuir probe measurements show that the mode modulates heat and particle fluxes to the target. The mode frequency appears to scale with the poloidal Alfven velocity, and not with sound speed (i.e. it is not a geodesic acoustic mode). A heuristic model is proposed for the frequency scaling of the mode. We discuss the relationship between the M-mode and other related observations near the L-H transition.

221. Modelling of JET DT experiments in ILW configurations

Author

Zagorski, R., Czarnecka, A., Ivanova-Stanik, I., Challis, C., Abduallev, S., Abhangi, M., Abreu, P., Afzal, M., Aggarwal, K. M., Ahlgren, T., Ahn, J. H., Aho-Mantila, L., Aiba, N., Airila, M., Albanese, R., Aldred, V., Alegre, D., Alessi, E., Aleynikov, P., Alfier, A., Alkseev, A., Allinson, M., Alper, B., Alves, E., Ambrosino, G., Ambrosino, R., Amicucci, L., Amosov, V., Sunden, E. Andersson, Angelone, M., Anghel, M., Angioni, C., Appel, L., Appelbee, C., Arena, P., Ariola, M., Arnichand, H., Arshad, S., Ash, A., Ashikawa, N., Aslanyan, V., Asunta, O., Auriemma, F., Austin, Y., Avotina, L., Axton, M. D., Ayres, C., Bacharis, M., Baciero, A., Baiao, D., Bailey, S., Baker, A., Balboa, I., Balden, M., Balshaw, N., Bament, R., Banks, J. W., Baranov, Y. F., Barnard, M. A., Barnes, D., Barnes, M., Barnsley, R., Wiechec, A. Baron, Orte, L. Barrera, Baruzzo, M., Basiuk, V., Bassan, M., Bastow, R., Batista, A., Batistoni, P., Baughan, R., Bauvir, B., Baylor, L., Bazylev, B., Beal, J., Beaumont, P. S., Beckers, M., Beckett, B., Becoulet, A., Bekris, N., Beldishevski, M., Bell, K., Belli, F., Bellinger, M., Belonohy, E., Ben Ayed, N., Benterman, N. A., Bergsaker, H., Bernardo, J., Bernert, M., Berry, M., Bertalot, L., Besliu, C., Beurskens, M., Bieg, B., Bielecki, J., Biewer, T., Bigi, M., Bilkova, P., Binda, F., Bisoffi, A., Bizarro, J. P. S., Bjorkas, C., Blackburn, J., Blackman, K., Blackman, T. R., Blanchard, P., Blatchford, P., Bobkov, V., Boboc, A., Bodnar, G., Bogar, O., Bolshakova, I., Bolzonella, T., Bonanomi, N., Bonelli, F., Boom, J., Booth, J., Borba, D., Borodin, D., Borodkina, I., Botrugno, A., Bottereau, C., Boulting, P., Bourdelle, C., Bowden, M., Bower, C., Bowman, C., Boyce, T., Boyd, C., Boyer, H. J., Bradshaw, J. M. A., Braic, V., Bravanec, R., Breizman, B., Bremond, S., Brennan, P. D., Breton, S., Brett, A., Brezinsek, S., Bright, M. D. J., Brix, M., Broeckx, W., Brombin, M., Broslawski, A., Brown, D. P. D., Brown, M., Bruno, E., Bucalossi, J., Buch, J., Buchanan, J., Buckley, M. A., Budny, R., Bufferand, H., Bulman, M., Bulmer, N., Bunting, P., Buratti, P., Burckhart, A., Buscarino, A., Busse, A., Butler, N. K., Bykov, I., Byrne, J., Cahyna, P., Calabro, G., Calvo, I., Camenen, Y., Camp, P., Campling, D. C., Cane, J., Cannas, B., Capel, A. J., Card, P. J., Cardinali, A., Carman, P., Carr, M., Carralero, D., Carraro, L., Carvalho, B. B., Carvalho, I., Carvalho, P., Casson, F. J., Castaldo, C., Catarino, N., Caumont, J., Causa, F., Cavazzana, R., Cave-Ayland, K., Cavinato, M., Cecconello, M., Ceccuzzi, S., Cecil, E., Cenedese, A., Cesario, R., Challis, C. D., Chandler, M., Chandra, D., Chang, C. S., Chankin, A., Chapman, I. T., Chapman, S. C., Chernyshova, M., Chitarin, G., Ciraolo, G., Ciric, D., Citrin, J., Clairet, F., Clark, E., Clark, M., Clarkson, R., Clatworthy, D., Clements, C., Cleverly, M., Coad, J. P., Coates, P. A., Cobalt, A., Coccorese, V., Cocilovo, V., Coda, S., Coelho, R., Coenen, J. W., Coffey, I., Colas, L., Collins, S., Conka, D., Conroy, S., Conway, N., Coombs, D., Cooper, D., Cooper, S. R., Corradino, C., Corre, Y., Corrigan, G., Cortes, S., Coster, D., Couchman, A. S., Cox, M. P., Craciunescu, T., Cramp, S., Craven, R., Crisanti, F., Croci, G., Croft, D., Crombe, K., Crowe, R., Cruz, N., Cseh, G., Cufar, A., Cullen, A., Curuia, M., Dabirikhah, H., Dalgliesh, P., Dalley, S., Dankowski, J., Darrow, D., Davies, O., Davis, W., Day, C., Day, I. E., De Bock, M., de Castro, A., de la Cal, E., de la Luna, E., De Masi, G., de Pablos, J. L., De Temmerman, G., De Tommasi, G., de Vries, P., Deakin, K., Deane, J., Agostini, F. Degli, Dejarnac, R., Delabie, E., den Harder, N., Dendy, R. O., Denis, J., Denner, P., Devaux, S., Devynck, P., Di Maio, F., Di Siena, A., Di Troia, C., Dinca, P., D'Inca, R., Ding, B., Dittmar, T., Doerk, H., Doerner, R. P., Donne, T., Dorling, S. E., Dormido-Canto, S., Doswon, S., Douai, D., Doyle, P. T., Drenik, A., Drewelow, P., Drews, P., Duckworth, Ph., Dumont, R., Dumortier, P., Dunai, D., Dunne, M., Duran, I., Durodie, F., Dutta, P., Duval, B. P., Dux, R., Dylst, K., Dzysiuk, N., Edappala, P. V., Edmond, J., Edwards, A. M., Edwards, J., Eich, Th., Ekedahl, A., El-Jorf, R., Elsmore, C. G., Enachescu, M., Ericsson, G., Eriksson, F., Eriksson, J., Eriksson, L. G., Esposito, B., Esquembri, S., Esser, H. G., Esteve, D., Evans, B., Evans, G. E., Evison, G., Ewart, G. D., Fagan, D., Faitsch, M., Falie, D., Fanni, A., Fasoli, A., Faustin, J. M., Fawlk, N., Fazendeiro, L., Fedorczak, N., Felton, R. C., Fenton, K., Fernades, A., Fernandes, H., Ferreira, J., Fessey, J. A., Fevrier, O., Ficker, O., Field, A., Fietz, S., Figueiredo, A., Figueiredo, J., Fil, A., Finburg, P., Firdaouss, M., Fischer, U., Fittill, L., Fitzgerald, M., Flammini, D., Flanagan, J., Fleming, C., Flinders, K., Fonnesu, N., Fontdecaba, J. M., Formisano, A., Forsythe, L., Fortuna, L., Fortuna-Zalesna, E., Fortune, M., Foster, S., Franke, T., Franklin, T., Frasca, M., Frassinetti, L., Freisinger, M., Fresa, R., Frigione, D., Fuchs, V., Fuller, D., Futatani, S., Fyvie, J., Gal, K., Galassi, D., Galazka, K., Galdon-Quiroga, J., Gallagher, J., Gallart, D., Galvao, R., Gao, X., Gao, Y., Garcia, J., Garcia-Carrasco, A., Garcia-Munoz, M., Gardarein, J. -L., Garzotti, L., Gaudio, P., Gauthier, E., Gear, D. F., Gee, S. J., Geiger, B., Gelfusa, M., Gerasimov, S., Gervasini, G., Gethins, M., Ghani, Z., Ghate, M., Gherendi, M., Giacalone, J. C., Giacomelli, L., Gibson, C. S., Giegerich, T., Gil, C., Gil, L., Gilligan, S., Gin, D., Giovannozzi, E., Girardo, J. B., Giroud, C., Giruzzi, G., Gloeggler, S., Godwin, J., Goff, J., Gohil, P., Goloborod'ko, V., Gomes, R., Goncalves, B., Goniche, M., Goodliffe, M., Goodyear, A., Gorini, G., Gosk, M., Goulding, R., Goussarov, A., Gowland, R., Graham, B., Graham, M. E., Graves, J. P., Grazier, N., Grazier, P., Green, N. R., Greuner, H., Grierson, B., Griph, F. S., Grisolia, C., Grist, D., Groth, M., Grove, R., Grundy, C. N., Grzonka, J., Guard, D., Guerard, C., Guillemaut, C., Guirlet, R., Gurl, C., Utoh, H. H., Hackett, L. J., Hacquin, S., Hagar, A., Hager, R., Hakola, A., Halitovs, M., Hall, S. J., Cook, S. P. Hallworth, Hamlyn-Harris, C., Hammond, K., Harrington, C., Harrison, J., Harting, D., Hasenbeck, F., Hatano, Y., Hatch, D. R., Haupt, T. D. V., Hawes, J., Hawkes, N. C., Hawkins, J., Hawkins, P., Haydon, P. W., Hayter, N., Hazel, S., Heesterman, P. J. L., Heinola, K., Hellesen, C., Hellsten, T., Helou, W., Hemming, O. N., Hender, T. C., Henderson, M., Henderson, S. S., Henriques, R., Hepple, D., Hermon, G., Hertout, P., Hidalgo, C., Highcock, E. G., Hill, M., Hillairet, J., Hillesheim, J., Hillis, D., Hizanidis, K., Hjalmarsson, A., Hobirk, J., Hodille, E., Hogben, C. H. A., Hogeweij, G. M. D., Hollingsworth, A., Hollis, S., Homfray, D. A., Horacek, J., Hornung, G., Horton, A. R., Horton, L. D., Horvath, L., Hotchin, S. P., Hough, M. R., Howarth, P. J., Hubbard, A., Huber, A., Huber, V., Huddleston, T. M., Hughes, M., Huijsmans, G. T. A., Hunter, C. L., Huynh, P., Hynes, A. M., Iglesias, D., Imazawa, N., Imbeaux, F., Imrisek, M., Incelli, M., Innocente, P., Irishkin, M., Jachmich, S., Jacobsen, A. S., Jacquet, P., Jansons, J., Jardin, A., Jarvinen, A., Jaulmes, F., Jednorog, S., Jenkins, I., Jeong, C., Jepu, I., Joffrin, E., Johnson, R., Johnson, T., Johnston, Jane, Joita, L., Jones, G., Jones, T. T. C., Hoshino, K. K., Kallenbach, A., Kamiya, K., Kaniewski, J., Kantor, A., Kappatou, A., Karhunen, J., Karkinsky, D., Karnowska, I., Kaufman, M., Kaveney, G., Kazakov, Y., Kazantzidis, V., Keeling, D. L., Keenan, T., Keep, J., Kempenaars, M., Kennedy, C., Kenny, D., Kent, J., Kent, O. N., Khilkevich, E., Kim, H. T., Kim, H. S., Kinch, A., King, C., King, D., King, R. F., Kinna, D. J., Kiptily, V., Kirk, A., Kirov, K., Kirschner, A., Kizane, G., Klepper, C., Klix, A., Knight, P., Knipe, S. J., Knott, S., Kobuchi, T., Koechl, F., Kocsis, G., Kodeli, I., Kogan, L., Kogut, D., Koivuranta, S., Kominis, Y., Koeppen, M., Kos, B., Koskela, T., Koslowski, H. R., Koubiti, M., Kovari, M., Kowalska-Strzeciwilk, E., Krasilnikov, A., Krasilnikov, V., Krawczyk, N., Kresina, M., Krieger, K., Krivska, A., Kruezi, U., Ksiazek, I., Kukushkin, A., Kundu, A., Kurki-Suonio, T., Kwak, S., Kwiatkowski, R., Kwon, O. J., Laguardia, L., Lahtinen, A., Laing, A., Lam, N., Lambertz, H. T., Lane, C., Lang, P. T., Lanthaler, S., Lapins, J., Lasa, A., Last, J. R., Laszynska, E., Lawless, R., Lawson, A., Lawson, K. D., Lazaros, A., Lazzaro, E., Leddy, J., Lee, S., Lefebvre, X., Leggate, H. J., Lehmann, J., Lehnen, M., Leichtle, D., Leichuer, P., Leipold, F., Lengar, I., Lennholm, M., Lerche, E., Lescinskis, A., Lesnoj, S., Letellier, E., Leyland, M., Leysen, W., Li, L., Liang, Y., Likonen, J., Linke, J., Linsmeier, Ch., Lipschultz, B., Liu, G., Liu, Y., Lo Schiavo, V. P., Loarer, T., Loarte, A., Lobel, R. C., Lomanowski, B., Lomas, P. J., Lonnroth, J., Lopez, J. M., Lopez-Razola, J., Lorenzini, R., Losada, U., Lovell, J. J., Loving, A. B., Lowry, C., Luce, T., Lucock, R. M. A., Lukin, A., Luna, C., Lungaroni, M., Lungu, C. P., Lungu, M., Lunniss, A., Lupelli, I., Lyssoivan, A., Macdonald, N., Macheta, P., Maczewa, K., Magesh, B., Maget, P., Maggi, C., Maier, H., Mailloux, J., Makkonen, T., Makwana, R., Malaquias, A., Malizia, A., Manas, P., Manning, A., Manso, M. E., Mantica, P., Mantsinen, M., Manzanares, A., Maquet, Ph., Marandet, Y., Marcenko, N., Marchetto, C., Marchuk, O., Marinelli, M., Marinucci, M., Markovic, T., Marocco, D., Marot, L., Marren, C. A., Marshal, R., Martin, A., Martin, Y., Martin de Aguilera, A., Martinez, F. J., Martin-Solis, J. R., Martynova, Y., Maruyama, S., Masiello, A., Maslov, M., Matejcik, S., Mattei, M., Matthews, G. F., Maviglia, F., Mayer, M., Mayoral, M. L., May-Smith, T., Mazon, D., Mazzotta, C., McAdams, R., McCarthy, P. J., McClements, K. G., McCormack, O., McCullen, P. A., McDonald, D., McIntosh, S., McKean, R., McKehon, J., Meadows, R. C., Meakins, A., Medina, F., Medland, M., Medley, S., Meigh, S., Meigs, A. G., Meisl, G., Meitner, S., Meneses, L., Menmuir, S., Mergia, K., Merrigan, I. R., Mertens, Ph., Meshchaninov, S., Messiaen, A., Meyer, H., Mianowski, S., Michling, R., Middleton-Gear, D., Miettunen, J., Militello, F., Militello-Asp, E., Miloshevsky, G., Mink, F., Minucci, S., Miyoshi, Y., Mlynar, J., Molina, D., Monakhov, I., Moneti, M., Mooney, R., Moradi, S., Mordijck, S., Moreira, L., Moreno, R., Moro, F., Morris, A. W., Morris, J., Moser, L., Mosher, S., Moulton, D., Murari, A., Muraro, A., Murphy, S., Asakura, N. N., Na, Y. S., Nabais, F., Naish, R., Nakano, T., Nardon, E., Naulin, V., Nave, M. F. F., Nedzelski, I., Nemtsev, G., Nespoli, F., Neto, A., Neu, R., Neverov, V. S., Newman, M., Nicholls, K. J., Nicolas, T., Nielsen, A. H., Nielsen, P., Nilsson, E., Nishijima, D., Noble, C., Nocente, M., Nodwell, D., Nordlund, K., Nordman, H., Nouailletas, R., Nunes, I., Oberkofler, M., Odupitan, T., Ogawa, M. T., O'Gorman, T., Okabayashi, M., Olney, R., Omolayo, O., O'Mullane, M., Ongena, J., Orsitto, F., Orszagh, J., Oswuigwe, B. I., Otin, R., Owen, A., Paccagnella, R., Pace, N., Pacella, D., Packer, L. W., Page, A., Pajuste, E., Palazzo, S., Pamela, S., Panja, S., Papp, P., Paprok, R., Parail, V., Park, M., Diaz, F. Parra, Parsons, M., Pasqualotto, R., Patel, A., Pathak, S., Paton, D., Patten, H., Pau, A., Pawelec, E., Soldan, C. Paz, Peackoc, A., Pearson, I. J., Pehkonen, S. -P., Peluso, E., Penot, C., Pereira, A., Pereira, R., Puglia, P. P. Pereira, von Thun, C. Perez, Peruzzo, S., Peschanyi, S., Peterka, M., Petersson, P., Petravich, G., Petre, A., Petrella, N., Petrzilka, V., Peysson, Y., Pfefferle, D., Philipps, V., Pillon, M., Pintsuk, G., Piovesan, P., Pires dos Reis, A., Piron, L., Pironti, A., Pisano, F., Pitts, R., Pizzo, F., Plyusnin, V., Pomaro, N., Pompilian, O. G., Pool, P. J., Popovichev, S., Porfiri, M. T., Porosnicu, C., Porton, M., Possnert, G., Potzel, S., Powell, T., Pozzi, J., Prajapati, V., Prakash, R., Prestopino, G., Price, D., Price, M., Price, R., Prior, P., Proudfoot, R., Pucella, G., Puglia, P., Puiatti, M. E., Pulley, D., Purahoo, K., Puetterich, Th., Rachlew, E., Rack, M., Ragona, R., Rainford, M. S. J., Rakha, A., Ramogida, G., Ranjan, S., Rapson, C. J., Rasmussen, J. J., Rathod, K., Ratta, G., Ratynskaia, S., Ravera, G., Rayner, C., Rebai, M., Reece, D., Reed, A., Refy, D., Regan, B., Regana, J., Reich, M., Reid, N., Reimold, F., Reinhart, M., Reinke, M., Reiser, D., Rendell, D., Reux, C., Reyes Cortes, S. D. A., Reynolds, S., Riccardo, V., Richardson, N., Riddle, K., Rigamonti, D., Rimini, F. G., Risner, J., Riva, M., Roach, C., Robins, R. J., Robinson, S. A., Robinson, T., Robson, D. W., Roccella, R., Rodionov, R., Rodrigues, P., Rodriguez, J., Rohde, V., Romanelli, F., Romanelli, M., Romanelli, S., Romazanov, J., Rowe, S., Rubel, M., Rubinacci, G., Rubino, G., Ruchko, L., Ruiz, M., Ruset, C., Rzadkiewicz, J., Saarelma, S., Sabot, R., Safi, E., Sagar, P., Saibene, G., Saint-Laurent, F., Salewski, M., Salmi, A., Salmon, R., Salzedas, F., Samaddar, D., Samm, U., Sandiford, D., Santa, P., Santala, M. I. K., Santos, B., Santucci, A., Sartori, F., Sartori, R., Sauter, O., Scannell, R., Schlummer, T., Schmid, K., Schmidt, V., Schmuck, S., Schneider, M., Schoepf, K., Schworer, D., Scott, S. D., Sergienko, G., Sertoli, M., Shabbir, A., Sharapov, S. E., Shaw, A., Shaw, R., Sheikh, H., Shepherd, A., Shevelev, A., Shumack, A., Sias, G., Sibbald, M., Sieglin, B., Silburn, S., Silva, A., Silva, C., Simmons, P. A., Simpson, J., Simpson-Hutchinson, J., Sinha, A., Sipila, S. K., Sips, A. C. C., Siren, P., Sirinelli, A., Sjostrand, H., Skiba, M., Skilton, R., Slabkowska, K., Slade, B., Smith, N., Smith, P. G., Smith, R., Smith, T. J., Smithies, M., Snoj, L., Soare, S., Solano, E. R., Somers, A., Sommariva, C., Sonato, P., Sopplesa, A., Sousa, J., Sozzi, C., Spagnolo, S., Spelzini, T., Spineanu, F., Stables, G., Stamatelatos, I., Stamp, M. F., Staniec, P., Stankunas, G., Stan-Sion, C., Stead, M. J., Stefanikova, E., Stepanov, I., Stephen, A. V., Stephen, M., Stevens, A., Stevens, B. D., Strachan, J., Strand, P., Strauss, H. R., Strom, P., Stubbs, G., Studholme, W., Subba, F., Summers, H. P., Svensson, J., Swiderski, L., Szabolics, T., Szawlowski, M., Szepesi, G., Suzuki, T. T., Tal, B., Tala, T., Talbot, A. R., Talebzadeh, S., Taliercio, C., Tamain, P., Tame, C., Tang, W., Tardocchi, M., Taroni, L., Taylor, D., Taylor, K. A., Tegnered, D., Telesca, G., Teplova, N., Terranova, D., Testa, D., Tholerus, E., Thomas, J., Thomas, J. D., Thomas, P., Thompson, A., Thompson, C. -A., Thompson, V. K., Thorne, L., Thornton, A., Thrysoe, A. S., Tigwell, P. A., Tipton, N., Tiseanu, I., Tojo, H., Tokitani, M., Tolias, P., Tomes, M., Tonner, P., Towndrow, M., Trimble, P., Tripsky, M., Tsalas, M., Tsavalas, P., Jun, D. Tskhakaya, Turner, I., Turner, M. M., Turnyanskiy, M., Tvalashvili, G., Tyrrell, S. G. J., Uccello, A., Ul-Abidin, Z., Uljanovs, J., Ulyatt, D., Urano, H., Uytdenhouwen, I., Vadgama, A. P., Valcarcel, D., Valentinuzzi, M., Valisa, M., Olivares, P. Vallejos, Valovic, M., Van De Mortel, M., Van Eester, D., Van Renterghem, W., van Rooij, G. J., Varje, J., Varoutis, S., Vartanian, S., Vasava, K., Vasilopoulou, T., Vega, J., Verdoolaege, G., Verhoeven, R., Verona, C., Rinati, G. Verona, Veshchev, E., Vianello, N., Vicente, J., Viezzer, E., Villari, S., Villone, F., Vincenzi, P., Vinyar, I., Viola, B., Vitins, A., Vizvary, Z., Vlad, M., Voitsekhovitch, I., Vondracek, P., Vora, N., Vu, T., Pires de Sa, W. W., Wakeling, B., Waldon, C. W. F., Walkden, N., Walker, M., Walker, R., Walsh, M., Wang, E., Wang, N., Warder, S., Warren, R. J., Waterhouse, J., Watkins, N. W., Watts, C., Wauters, T., Weckmann, A., Weiland, J., Weisen, H., Weiszflog, M., Wellstood, C., West, A. T., Wheatley, M. R., Whetham, S., Whitehead, A. M., Whitehead, B. D., Widdowson, A. M., Wiesen, S., Wilkinson, J., Williams, J., Williams, M., Wilson, A. R., Wilson, D. J., Wilson, H. R., Wilson, J., Wischmeier, M., Withenshaw, G., Withycombe, A., Witts, D. M., Wood, D., Wood, R., Woodley, C., Wray, S., Wright, J., Wright, J. C., Wu, J., Wukitch, S., Wynn, A., Xu, T., Yadikin, D., Yanling, W., Yao, L., Yavorskij, V., Yoo, M. G., Young, C., Young, D., Young, I. D., Young, R., Zacks, J., Zaitsev, F. S., Zanino, R., Zarins, A., Zastrow, K. D., Zerbini, M., Zhang, W., Zhou, Y., Zilli, E., Zoita, V., Zoletnik, S., and Zychor, I.

Subjects
tritium, integrated modelling, food and beverages, jet seeding discharges, edge plasma, discharges, h-mode, core plasma
Abstract

Numerical scan at constant shows that core and scrape-off layer (SOL) radiations do not depend on the plasma current (I-p). Whereas the SOL radiation increases with seeding, the core radiation, however, does not continue to increase with seeding but rolls over at higher seeding rates in the simulations. The core plasma contamination by W ions is low, c(W) << 10(-4). When the seeding starts, an increase in radiation power leading to a reduction in P-loss = (P-aux - P-rad) is observed, influencing the plasma confinement. The power scan at constant I-p indicates that the core radiation, P-plate, P-SOL (and even SOL radiation), saturates with seeding. In addition, strong dilution with increasing seeding (Z(eff) >> 3) and large W concentrations with increasing power are found. Comparing neon with nitrogen seeding, it is seen that neon leads to slightly larger total radiation than nitrogen. However, that is achieved with much higher plasma contamination (Z(eff) approximate to 4-5) and dilution in the case of Ne, and simultaneously the power crossing the separatrix is lower for Ne than for N, indicating better H-mode performance in N-2-seeded discharges.

222. I-mode studies at ASDEX Upgrade: L-I and I-H transitions, pedestal and confinement properties

Author

Julia Fuchs, B. Kurzan, W. Suttrop, M. Bernert, S. da Graca, R. M. McDermott, R. Fischer, E. Wolfrum, A. Burckhart, F. Ryter, M. Willensdorfer, E. Viezzer, Th. Pütterich, L. Barrera Orte, T. Happel, Patrick J. McCarthy, Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, European Commission (EC), and ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Nuclear and High Energy Physics, Tokamak, Materials science, Transport, 01 natural sciences, 7. Clean energy, Flattening, 010305 fluids & plasmas, law.invention, Ion, Optics, Pedestal, ASDEX Upgrade, law, Physics::Plasma Physics, 0103 physical sciences, 010306 general physics, Pressure gradient, business.industry, I-mode, Plasma, Condensed Matter Physics, Computational physics, Magnetic field, H-mode, business
Abstract

The I-mode is a plasma regime obtained when the usual L-H power threshold is high, e.g. with unfavourable ion ∇ B direction. It is characterised by the development of a temperature pedestal while the density remains roughly as in the L-mode. This leads to a confinement improvement above the L-mode level which can sometimes reach H-mode values. This regime, already obtained in the ASDEX Upgrade tokamak about two decades ago, has been studied again since 2009 taking advantage of the development of new diagnostics and heating possibilities. The I-mode in ASDEX Upgrade has been achieved with different heating methods such as NBI, ECRH and ICRF. The I-mode properties, power threshold, pedestal characteristics and confinement, are independent of the heating method. The power required at the L-I transition exhibits an offset linear density dependence but, in contrast to the L-H threshold, depends weakly on the magnetic field. The L-I transition seems to be mainly determined by the edge pressure gradient and the comparison between ECRH and NBI induced L-I transitions suggests that the ion channel plays a key role. The I-mode often evolves gradually over a few confinement times until the transition to H-mode which offers a very interesting situation to study the transport reduction and its link with the pedestal formation. Exploratory discharges in which n = 2 magnetic perturbations have been applied indicate that these can lead to an increase of the I-mode power threshold by flattening the edge pressure at fixed heating input power: more heating power is necessary to restore the required edge pressure gradient. Finally, the confinement properties of the I-mode are discussed in detail.

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223. Dimensionless parameter scaling of intrinsic torque in C-Mod enhanced confinement plasmas

Author

Tuomas Tala, Earl Marmar, A. Salmi, N. M. Cao, Martin Greenwald, J. E. Rice, P. Rodriguez Fernandez, Colin Chrystal, J. W. Hughes, and Matthew Reinke

Subjects
Physics, Nuclear and High Energy Physics, Tokamak, I-mode, Plasma, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, law.invention, H-mode, Intrinsic torque, law, Quantum electrodynamics, Mod, 0103 physical sciences, Torque, 010306 general physics, Scaling, Dimensionless quantity
Abstract

A dimensionless parameter dependence study of intrinsic torque has been performed on a database of H- and I-mode plasmas from the Alcator C-Mod tokamak. The torque was determined by comparing intrinsic angular momentum density profiles just before and just after L–H and L–I transitions. The intrinsic torque has been found to scale as β N 1.5 ρ * − 1.0 ν * 0.1 , with the parameter ranges 0.3 ⩽ β N ⩽ 1.5, 0.004 ⩽ ρ * ⩽ 0.011 and 0.04 ⩽ ν * ⩽ 0.9. Comparison with results from JET and DIII-D suggests that the intrinsic torque should be normalized by some measure of the device size. Depending upon this normalization, the estimated total intrinsic torques for ITER, SPARC and ARC are ∼20, ∼4 and ∼8 Nm, respectively.

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224. Isotope dependence of the type I ELMy H-mode pedestal in JET-ILW hydrogen and deuterium plasmas

Author

A. Boboc, H. Weisen, D. L. Keeling, S. Aleiferis, C. Giroud, L. Horvath, A. R. Field, S. A. Silburn, M. Maslov, J. Simpson, C. F. Maggi, Eva Belonohy, Jet Contributors, J. Flanagan, S. Saarelma, G. F. Matthews, G. Corrigan, A. V. Chankin, E. Delabie, K. J. Gibson, D. King, D. Harting, A. C. C. Sips, Lorenzo Frassinetti, S. Menmuir, Culham Science Centre, Max-Planck-Institut für Plasmaphysik, Demokritos National Centre for Scientific Research, Oak Ridge National Laboratory, KTH Royal Institute of Technology, Department of Applied Physics, Swiss Federal Institute of Technology Lausanne, University of York, Aalto-yliopisto, Aalto University, and JET Contributors

Subjects
Nuclear and High Energy Physics, Materials science, Hydrogen, JET-ILW, chemistry.chemical_element, h-mode, 01 natural sciences, 010305 fluids & plasmas, Pedestal, 0103 physical sciences, 010306 general physics, tokamak, Jet (fluid), Divertor, Plasma, Condensed Matter Physics, jet-ilw, H-mode, Deuterium, chemistry, confinement, Electron temperature, Magnetohydrodynamics, Atomic physics, isotope effect, pedestal
Abstract

The pedestal structure, edge transport and linear MHD stability have been analyzed in a series of JET with the ITER-like wall hydrogen (H) and deuterium (D) type I ELMy H-mode plasmas. The pedestal pressure is typically higher in D than in H at the same input power and gas rate, with the difference mainly due to lower density in H than in D (Maggi et al (JET Contributors) 2018 Plasma Phys. Control. Fusion 60 014045). A power balance analysis of the pedestal has shown that higher inter-ELM separatrix loss power is required in H than in D to maintain a similar pedestal top pressure. This is qualitatively consistent with a set of interpretative EDGE2D-EIRENE simulations for H and D plasmas, showing that higher edge particle and heat transport coefficients are needed in H than in D to match the experimental profiles. It has also been concluded that the difference in neutral penetration between H and D leads only to minor changes in the upstream density profiles and with trends opposite to experimental observations. This implies that neutral penetration has a minor role in setting the difference between H and D pedestals, but higher ELM and/or inter-ELM transport are likely to be the main players. The interpretative EDGE2D-EIRENE simulations, with simultaneous upstream and outer divertor target profile constraints, have indicated higher separatrix electron temperature in H than in D for a pair of discharges at low fueling gas rate and similar stored energy (which required higher input power in H than in D at the same gas rate). The isotope dependence of linear MHD pedestal stability has been found to be small, but if a higher separatrix temperature is considered in H than in D, this could lead to destabilization of peeling-ballooning modes and shrinking of the stability boundary, qualitatively consistent with the reduced pedestal confinement in H.

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