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3. Extension of the multi-frequency ECRH system at ASDEX upgrade

Author

Wagner D., Stober J., Kircher M., Leuterer F., Monaco F., Münich M., Schubert M., Zohm H., Gantenbein G., Jelonnek J., Thumm M., Meier A., Scherer T., Strauss D., Kasparek W., Lechte C., Plaum B., Zach A., Litvak A.G., Denisov G.G., Chirkov A., Malygin V., Popov L.G., Nichiporenko V.O., Myasnikov V.E., Tai E.M., Solyanova E.A., and Malygin S.A.

Subjects
Physics, QC1-999
Published
2017
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4. High power ECRH and ECCD in moderately collisional ASDEX Upgrade Hmodes and status of EC system upgrade

Author

Stober J., Sommer F., Angioni C., Bock A., Fable E., Leuterer F., Monaco F., Müller F., Münich S., Petzold B., Poli E., Schubert M., Schütz H., Wagner D., Zohm H., Kasparek W., Plaum B., Meier A., Scherer Th., Strauß D., Jelonnek J., Thumm M., Litvak A., Denisov G.G., Chirkov A.V., Tai E.M., Popov L.G., Nichiporenko V.O., Myasnikov V.E., Soluyanova E.A., and Malygin V.

Subjects
Physics, QC1-999
Abstract

This contribution deals with H-modes with significant heat exchange between electrons and ions, but which can still show large differences between electron and ion-temperatures especially inside half minor radius. These conditions are referred to as moderately collisional. A systematic study shows that an increasing fraction of electron heating increases the transport in the ion channel mainly due to the dependence of the ITG dominated ion transport on the ratio Te/Ti in agreement with modeling. The rotational shear in the plasmas under study was so small that it hardly influences ITG stability, such that variations of the rotation profile due to a change of the heating method were of minor importance. These findings connect to studies of advanced tokamak scenarios using ECCD as a tool to modify the q-profile. The electron heating connected to the ECCD tends to increase the transport in the ion channel quite in contrast to the goal to operate at reduced current but with increased confinement. The confinement only increases as the fraction of ion heating is increased by adding more NBI. An ITER case was modeled as well. Due to the larger value of νei ・ τE the ratio Te/Ti is only moderately reduced even with strong electron heating and the confinement reduction is small even for the hypothetic case of using only ECRH as additional heating. Finally the paper discusses the ongoing upgrade of the AUG ECRH-system.

Published
2015
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5. A Multifrequency Notch Filter for Millimeter Wave Plasma Diagnostics based on Photonic Bandgaps in Corrugated Circular Waveguides

Author

Wagner D., Bongers W., Kasparek W., Leuterer F., Monaco F., Münich M., Schütz H., Stober J., Thumm M., and Brand H. v.d.

Subjects
Physics, QC1-999
Abstract

Sensitive millimeter wave diagnostics need often to be protected against unwanted radiation like, for example, stray radiation from high power Electron Cyclotron Heating applied in nuclear fusion plasmas. A notch filter based on a waveguide Bragg reflector (photonic band-gap) may provide several stop bands of defined width within up to two standard waveguide frequency bands. A Bragg reflector that reflects an incident fundamental TE11 into a TM1n mode close to cutoff is combined with two waveguide tapers to fundamental waveguide diameter. Here the fundamental TE11 mode is the only propagating mode at both ends of the reflector. The incident TE11 mode couples through the taper and is converted to the high order TM1n mode by the Bragg structure at the specific Bragg resonances. The TM1n mode is trapped in the oversized waveguide section by the tapers. Once reflected at the input taper it will be converted back into the TE11 mode which then can pass through the taper. Therefore at higher order Bragg resonances, the filter acts as a reflector for the incoming TE11 mode. Outside of the Bragg resonances the TE11 mode can propagate through the oversized waveguide structure with only very small Ohmic attenuation compared to propagating in a fundamental waveguide. Coupling to other modes is negligible in the non-resonant case due to the small corrugation amplitude (typically 0.05·λ0, where λ0 is the free space wavelength). A Bragg reflector for 105 and 140 GHz was optimized by mode matching (scattering matrix) simulations and manufactured by SWISSto12 SA, where the required mechanical accuracy of ± 5 μm could be achieved by stacking stainless steel rings, manufactured by micro-machining, in a high precision guiding pipe. The two smooth-wall tapers were fabricated by electroforming. Several measurements were performed using vector network analyzers from Agilent (E8362B), ABmm (MVNA 8-350) and Rohde&Schwarz (ZVA24) together with frequency multipliers. The stop bands around 105 GHz (- 55dB) and 140 GHz (-60dB) correspond to the TE11-TM12 and TE11-TM13 Bragg resonances. Experiments are in good agreement with theory.

Published
2015
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6. ECRH on ASDEX Upgrade - System Status, Feed-Back Control, Plasma Physics Results

Author

Flamm J., Vaccaro A., Strauβ D., Scherer Th., Meier A., Stroth U., Kasparek W., Zohm H., Schütz H., Schubert M., Poli E., Münich M., Müller S., Mlynek A., Marascheck M., Monaco F., Leuterer F., Herrmann A., Gianone L., Wagner D., Treutterer W., Sommer F., Reich M., Höhnle H., Bock A., Stober J., Thumm M., Litvak A., Denisov G.G., Chirkov A.V., Tai E.M., Popov L.G., Nichiporenko V.O., Myasnikov V.E., Soluyanova E.A., and Malygin S.A.

Subjects
Physics, QC1-999
Abstract

The ASDEX Upgrade (AUG) ECRH system now delivers a total of 3.9 MW to the plasma at 140 GHz. Three new units are capable of 2-frequency operation and may heat the plasma alternatively with 2.1 MW at 105 GHz. The system is routinely used with X2, O2, and X3 schemes. For Bt = 3.2 T also an ITER-like O1-scheme can be run using 105 GHz. The new launchers are capable of fast poloidal movements necessary for real-time control of the location of power deposition. Here real-time control of NTMs is summarized, which requires a fast analysis of massive data streams (ECE and Mirnov correlation) and extensive calculations (equilibria, ray-tracing). These were implemented at AUG using a modular concept of standardized real-time diagnostics. The new realtime capabilities have also been used during O2 heating to keep the first reflection of the non-absorbed beam fraction on the holographic reflector tile which ensures a well defined second pass of the beam through the central plasma. Sensors for the beam position are fast thermocouples at the edge of the reflector tile. The enhanced ECRH power was used for several physics studies related to the unique feature of pure electron heating without fueling and without momentum input. As an example the effect of the variation of the heating mix in moderately heated H-modes is demonstrated using the three available heating systems, i.e. ECRH, ICRH and NBI. Keeping the total input power constant, strong effects are seen on the rotation, but none on the pedestal parameters. Also global quantities as the stored energy are hardly modified. Still it is found that the central ion temperature drops as the ECRH fraction exceeds a certain threshold.

Published
2012
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8. Plasma Confinement in Stellarator Systems

Author

Bartlett, D. V., Cannici, G., Cattanei, G., Dorst, D., Elsner, A., Feist, J. H., Grieger, G., Hacker, H., How, J., Jaeckel, H., Jaenicke, R., Javel, P., Junker, J., Kick, M., Lathe, R., Leuterer, F., Lister, G. G., Mahn, C., Marlier, S., Mueller, G., Ohlendorf, W., Ott, W., Rau, F., Renner, H., Ringler, H., Saffert, J., Sapper, J., Smeulders, R., Speth, E., Tutter, M., Weller, A., Wuersching, E., Wobig, H., Dellis, A. N., Johnson, P. C., Lees, D. J., Lomas, P. J., Selden, A. C., Thomas, P. R., and Lloyd, B.

Published
1981

11. Status of the new ECRH system for ASDEX Upgrade

Author

Leuterer, F., Grünwald, G., Monaco, F., Münich, M., Schütz, H., Ryter, F., Wagner, D., Zohm, H., Franke, T., Dammertz, G., Heidinger, R., Koppenburg, K., Thumm, M., Kasparek, W., Gantenbein, G., Hailer, H., Denisov, G.G., Litvak, A., and Zapevalov, V.

Published
2005
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14. Plans for a new ECRH system at ASDEX upgrade

Author

Leuterer, F., Kirov, K., Monaco, F., Münich, M., Schütz, H., Ryter, F., Wagner, D., Wilhelm, R., Zohm, H., Franke, T., Voigt, K., Thumm, M., Heidinger, R., Dammertz, G., Koppenburg, K., Gantenbein, G., Hailer, H., Kasparek, W., Müller, G.A., Bogdashov, A., Denisov, G., Kurbatov, V., Kuftin, A., Litvak, A., Malygin, S., Tai, E., and Zapevalov, V.

Published
2003
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15. The ECRH system of ASDEX Upgrade

Author

Leuterer, F, Beckmann, M, Borchegowski, A, Brinkschulte, H, Chirkov, A, Denisov, G, Empacher, L, Förster, W, Gantenbein, G, Illin, V, Kasparek, W, Kirov, K, Monaco, F, Münich, M, Popov, L, Ryter, F, Schüller, P, Schwörer, K, and Schütz, H

Published
2001
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16. Experience with the ECRH system of ASDEX-Upgrade

Author

Leuterer, F, Beckmann, M, Brinkschulte, H, Monaco, F, Münich, M, Ryter, F, Schütz, H, Empacher, L, Gantenbein, G, Förster, W, Kasparek, W, Schüller, P, Schwörer, K, Borchegowski, A, Fix, A, Illin, V, Popov, L, Sigalaev, V, and Tai, E

Published
2001
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19. Recent ASDEX Upgrade research in support of ITER and DEMO

Author

Zohm, H, Ahn, J, Aho Mantila, L, Äkäslompolo, S, Angioni, C, Asunta, O, de Baar, M, Balden, M, Barrera Orte, L, Behler, K, Belapure, J, Bergmann, A, Bernardo, J, Bernert, M, Beurskens, M, Biancalani, A, Bilato, R, Birkenmeier, G, Bobkov, V, Bock, A, Bogomolov, A, Bolzonella, T, Boom, J, Böswirth, B, Bottereau, C, Bottino, A, van den Brand, H, Braun, F, Brezinsek, S, Brochard, F, Buhler, A, Burckhart, A, Camenen, Y, Carvalho, P, Carrasco, G, Cazzaniga, C, Carralero, D, Casali, L, Cavedon, M, Challis, C, Chankin, A, Chapman, I, Clairet, F, Classen, I, Coda, S, Coelho, R, Coenen, J, Colas, L, Conway, G, Costea, S, Coster, D, CROCI, GABRIELE, Cseh, G, Czarnecka, A, Day, C, de Marné, P, Denner, P, D'Inca, R, Douai, D, Drube, R, Dunne, M, Duval, B, Dux, R, Eich, T, Elgeti, S, Engelhardt, K, Ertl, K, Esposito, B, Fable, E, Fantz, U, Faugel, H, Felici, F, Fietz, S, Figueredo, A, Fischer, R, Ford, O, Franzen, P, Frassinetti, L, Fröschle, M, Fuchert, G, Fünfgelder, H, Fuchs, J, Gál, K, Garavaglia, S, Garcia Muñoz, M, Geiger, B, Giannone, L, Giovannozzi, E, Gleason González, C, Görler, T, Goodman, T, GORINI, GIUSEPPE, da Graca, S, Gräter, A, Granucci, G, Greuner, H, Grießhammer, J, Groth, M, Gude, A, Günter, S, Guimarais, L, Haas, G, Hakola, A, Happel, T, Harrison, J, Hatch, D, Hauer, V, Hauff, T, Heinemann, B, Heinzel, S, Hellsten, T, Hennequin, P, Herrmann, A, Heyn, E, Hobirk, J, Hölzl, M, Höschen, T, Holm, J, Hopf, C, Hoppe, F, Horvath, L, Houben, A, Huber, A, Igochine, V, Ilkei, T, Jacob, W, Jacobsen, A, Jacquot, J, Janzer, M, Jaulmes, F, Jenko, F, Jensen, T, Joffrin, E, Käsemann, C, Kallenbach, A, Kálvin, S, Kantor, M, Kappatou, A, Kardaun, O, Karhunen, J, Kim, D, Kimmig, S, Kirk, A, J, Klingshirn, H, Kocan, M, Koch, F, Kocsis, G, Köhn, A, Köppen, M, Kötterl, J, Koslowski, R, Koubiti, M, Kraus, M, Krieger, K, Krivska, A, Kogut, D, Krämer Flecken, A, Kurki Suonio, T, Kurzan, B, Lackner, K, Laggner, F, Lang, P, Lauber, P, Lazányi, N, Lazaros, A, Lebschy, A, Leuterer, F, Liang, Y, Linsmeier, h, Lipschultz, B, Litnovski, A, Lohs, A, Luhmann, N, Lunt, T, Lyssoivan, A, Madsen, J, Maier, H, Maj, O, Mailloux, J, Maljaars, E, Mancini, A, Manhard, A, Mank, K, E, Manso, M, Mantica, P, Mantsinen, M, Manz, P, Maraschek, M, Markina, E, Martens, C, Martin, P, Mayer, A, Mayer, M, Mazon, D, McCarthy, P, McDermott, R, Meisl, G, Meister, H, Medvedeva, A, Merkel, P, Merkel, R, Mertens, V, Meyer, H, Meyer, O, Milanesio, D, Miettunen, J, Mlynek, A, Monaco, F, Moro, A, Moseev, D, Müller, H, Müller, S, Münich, M, Nabais, F, Nemes Czopf, A, Neu, G, Neu, R, Nielsen, A, Nikolaeva, V, Nielsen, S, NOCENTE, MASSIMO, Nold, B, M, Noterdaeme, J, Nowak, S, Oberkofler, M, Ochoukov, R, Odstrcil, T, Papp, G, Park, H, Pau, A, Pautasso, G, Penzel, F, Petersson, P, Piovesan, P, Piron, C, Plaum, B, Plöckl, B, Plyusnin, V, Podoba, Y, Pokol, G, Pompon, F, Poli, E, Polozhiy, K, Porte, L, Potzel, S, Preuss, R, Prisiazhniuk, D, Pütterich, T, Ramish, M, Rapson, C, Rasmussen, J, Rathgeber, S, Raupp, G, Réfy, D, Reich, M, Reimold, F, Reinke, M, Ribeiro, T, Riedl, R, Rittich, D, Rocchi, G, Rodriguez Ramos, M, Rohde, V, Roth, J, Rott, M, Rubel, M, Ryter, F, Saarelma, S, Salewski, M, Salmi, A, Sanchis Sanchez, L, Santos, G, Santos, J, Sauter, O, Scarabosio, A, Schall, G, Schmid, K, Schmitz, O, Schneider, P, Schneider, W, Schneller, M, Schrittwieser, R, Schubert, M, Schwarz Selinger, T, Schweinzer, J, Scott, B, Sehmer, T, Sertoli, M, Shalpegin, A, Sias, G, Siccinio, M, Sieglin, B, Sigalov, A, Silva, A, Silva, C, Simon, P, Simpson, J, Snicker, A, Sommer, F, Sozzi, C, Spolaore, M, Stejner, M, Stober, J, Stobbe, F, Stroth, U, Strumberger, E, Sugiyama, K, J, Sun, Suttrop, W, Szepesi, T, Tál, B, Tala, T, Tardini, G, Tichmann, C, Told, D, Tophøj, L, Tudisco, O, von Toussaint, U, Trevisan, G, Treutterer, W, Tripský, M, Valisa, M, Valovic, M, Varela, P, Varoutis, S, Vezinet, D, Vianello, N, Vicente, J, Vierle, T, Viezzer, E, Vorpahl, C, Wagner, D, Wang, X, Wauters, T, Weidl, I, Weiland, M, Weller, A, Wenninger, R, Wieland, B, Wiesinger, M, Willensdorfer, M, Wiringer, B, Wischmeier, M, Wolf, R, Wolfrum, E, Wünderlich, D, Würsching, E, Yang, Z, Yu, Q, Zammuto, I, Zarzoso, D, Zasche, D, van Zeeland, M, Zehetbauer, T, Zilker, M., Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, European Commission (EC), Science and Technology of Nuclear Fusion, Zohm, H, Ahn, J, Aho Mantila, L, Äkäslompolo, S, Angioni, C, Asunta, O, de Baar, M, Balden, M, Barrera Orte, L, Behler, K, Belapure, J, Bergmann, A, Bernardo, J, Bernert, M, Beurskens, M, Biancalani, A, Bilato, R, Birkenmeier, G, Bobkov, V, Bock, A, Bogomolov, A, Bolzonella, T, Boom, J, Böswirth, B, Bottereau, C, Bottino, A, van den Brand, H, Braun, F, Brezinsek, S, Brochard, F, Buhler, A, Burckhart, A, Camenen, Y, Carvalho, P, Carrasco, G, Cazzaniga, C, Carralero, D, Casali, L, Cavedon, M, Challis, C, Chankin, A, Chapman, I, Clairet, F, Classen, I, Coda, S, Coelho, R, Coenen, J, Colas, L, Conway, G, Costea, S, Coster, D, Croci, G, Cseh, G, Czarnecka, A, Day, C, de Marné, P, Denner, P, D'Inca, R, Douai, D, Drube, R, Dunne, M, Duval, B, Dux, R, Eich, T, Elgeti, S, Engelhardt, K, Ertl, K, Esposito, B, Fable, E, Fantz, U, Faugel, H, Felici, F, Fietz, S, Figueredo, A, Fischer, R, Ford, O, Franzen, P, Frassinetti, L, Fröschle, M, Fuchert, G, Fünfgelder, H, Fuchs, J, Gál, K, Garavaglia, S, Garcia Muñoz, M, Geiger, B, Giannone, L, Giovannozzi, E, Gleason González, C, Görler, T, Goodman, T, Gorini, G, da Graca, S, Gräter, A, Granucci, G, Greuner, H, Grießhammer, J, Groth, M, Gude, A, Günter, S, Guimarais, L, Haas, G, Hakola, A, Happel, T, Harrison, J, Hatch, D, Hauer, V, Hauff, T, Heinemann, B, Heinzel, S, Hellsten, T, Hennequin, P, Herrmann, A, Heyn, E, Hobirk, J, Hölzl, M, Höschen, T, Holm, J, Hopf, C, Hoppe, F, Horvath, L, Houben, A, Huber, A, Igochine, V, Ilkei, T, Jacob, W, Jacobsen, A, Jacquot, J, Janzer, M, Jaulmes, F, Jenko, F, Jensen, T, Joffrin, E, Käsemann, C, Kallenbach, A, Kálvin, S, Kantor, M, Kappatou, A, Kardaun, O, Karhunen, J, Kim, D, Kimmig, S, Kirk, A, J, K, H, Kocan, M, Koch, F, Kocsis, G, Köhn, A, Köppen, M, Kötterl, J, Koslowski, R, Koubiti, M, Kraus, M, Krieger, K, Krivska, A, Kogut, D, Krämer Flecken, A, Kurki Suonio, T, Kurzan, B, Lackner, K, Laggner, F, Lang, P, Lauber, P, Lazányi, N, Lazaros, A, Lebschy, A, Leuterer, F, Liang, Y, Linsmeier, H, Lipschultz, B, Litnovski, A, Lohs, A, Luhmann, N, Lunt, T, Lyssoivan, A, Madsen, J, Maier, H, Maj, O, Mailloux, J, Maljaars, E, Mancini, A, Manhard, A, Mank, K, E, M, M, Mantica, P, Mantsinen, M, Manz, P, Maraschek, M, Markina, E, Martens, C, Martin, P, Mayer, A, Mayer, M, Mazon, D, Mccarthy, P, Mcdermott, R, Meisl, G, Meister, H, Medvedeva, A, Merkel, P, Merkel, R, Mertens, V, Meyer, H, Meyer, O, Milanesio, D, Miettunen, J, Mlynek, A, Monaco, F, Moro, A, Moseev, D, Müller, H, Müller, S, Münich, M, Nabais, F, Nemes Czopf, A, Neu, G, Neu, R, Nielsen, A, Nikolaeva, V, Nielsen, S, Nocente, M, Nold, B, M, N, J, Nowak, S, Oberkofler, M, Ochoukov, R, Odstrcil, T, Papp, G, Park, H, Pau, A, Pautasso, G, Penzel, F, Petersson, P, Piovesan, P, Piron, C, Plaum, B, Plöckl, B, Plyusnin, V, Podoba, Y, Pokol, G, Pompon, F, Poli, E, Polozhiy, K, Porte, L, Potzel, S, Preuss, R, Prisiazhniuk, D, Pütterich, T, Ramish, M, Rapson, C, Rasmussen, J, Rathgeber, S, Raupp, G, Réfy, D, Reich, M, Reimold, F, Reinke, M, Ribeiro, T, Riedl, R, Rittich, D, Rocchi, G, Rodriguez Ramos, M, Rohde, V, Roth, J, Rott, M, Rubel, M, Ryter, F, Saarelma, S, Salewski, M, Salmi, A, Sanchis Sanchez, L, Santos, G, Santos, J, Sauter, O, Scarabosio, A, Schall, G, Schmid, K, Schmitz, O, Schneider, P, Schneider, W, Schneller, M, Schrittwieser, R, Schubert, M, Schwarz Selinger, T, Schweinzer, J, Scott, B, Sehmer, T, Sertoli, M, Shalpegin, A, Sias, G, Siccinio, M, Sieglin, B, Sigalov, A, Silva, A, Silva, C, Simon, P, Simpson, J, Snicker, A, Sommer, F, Sozzi, C, Spolaore, M, Stejner, M, Stober, J, Stobbe, F, Stroth, U, Strumberger, E, Sugiyama, K, J, S, Suttrop, W, Szepesi, T, Tál, B, Tala, T, Tardini, G, Tichmann, C, Told, D, Tophøj, L, Tudisco, O, von Toussaint, U, Trevisan, G, Treutterer, W, Tripský, M, Valisa, M, Valovic, M, Varela, P, Varoutis, S, Vezinet, D, Vianello, N, Vicente, J, Vierle, T, Viezzer, E, Vorpahl, C, Wagner, D, Wang, X, Wauters, T, Weidl, I, Weiland, M, Weller, A, Wenninger, R, Wieland, B, Wiesinger, M, Willensdorfer, M, Wiringer, B, Wischmeier, M, Wolf, R, Wolfrum, E, Wünderlich, D, Würsching, E, Yang, Z, Yu, Q, Zammuto, I, Zarzoso, D, Zasche, D, van Zeeland, M, Zehetbauer, T, Zilker, M, Max-Planck-Institut für Plasmaphysik [Garching] (IPP), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, and EUROfusion MST1 Team

Subjects
Nuclear and High Energy Physics, Tokamak, Cyclotron, Condensed Matter Physic, Collisionality, 01 natural sciences, Resonant magnetic perturbations, Electron cyclotron resonance, 010305 fluids & plasmas, law.invention, Nuclear physics, ASDEX Upgrade, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], law, ITER, 0103 physical sciences, 010306 general physics, Edge-localized mode, tokamak physic, DEMO, nuclear fusion, Physics, Divertor, Condensed Matter Physics, Tokamak physics, Nuclear fusion, tokamak physics
Abstract

Recent experiments on the ASDEX Upgrade tokamak aim at improving the physics base for ITER and DEMO to aid the machine design and prepare efficient operation. Type I edge localized mode (ELM) mitigation using resonant magnetic perturbations (RMPs) has been shown at low pedestal collisionality ( ν ∗ ped < 0 . 4 ) . In contrast to the previous high ν ∗ regime, suppression only occurs in a narrow RMP spectral window, indicating a resonant process, and a concomitant confinement drop is observed due to a reduction of pedestal top density and electron temperature. Strong evidence is found for the ion heat flux to be the decisive element for the L–H power threshold. A physics based scaling of the density at which the minimum P LH occurs indicates that ITER could take advantage of it to initiate H-mode at lower density than that of the final Q = 10 operational point. Core density fluctuation measurements resolved in radius and wave number show that an increase of R/L T e introduced by off-axis electron cyclotron resonance heating (ECRH) mainly increases the large scale fluctuations. The radial variation of the fluctuation level is in agreement with simulations using the GENE code. Fast particles are shown to undergo classical slowing down in the absence of large scale magnetohydrodynamic (MHD) events and for low heating power, but show signs of anomalous radial redistribution at large heating power, consistent with a broadened off-axis neutral beam current drive current profile under these conditions. Neoclassical tearing mode (NTM) suppression experiments using electron cyclotron current drive (ECCD) with feedback controlled deposition have allowed to test several control strategies for ITER, including automated control of (3,2) and (2,1) NTMs during a single discharge. Disruption mitigation studies using massive gas injection (MGI) can show an increased fuelling efficiency with high field side injection, but a saturation of the fuelling efficiency is observed at high injected mass as needed for runaway electron suppression. Large locked modes can significantly decrease the fuelling efficiency and increase the asymmetry of radiated power during MGI mitigation. Concerning power exhaust, the partially detached ITER divertor scenario has been demonstrated at P sep /R = 10 MW m − 1 in ASDEX Upgrade, with a peak time averaged target load around 5MWm − 2 , well consistent with the component limits for ITER. Developing this towards DEMO, full detachment was achieved at P sep /R = 7MWm − 1 and stationary discharges with core radiation fraction of the order of DEMO requirements (70% instead of the 30% needed for ITER) were demonstrated. Finally, it remains difficult to establish the standard ITER Q = 10 scenario at low q 95 = 3 in the all-tungsten (all-W) ASDEX Upgrade due to the observed poor confinement at low β N . This is mainly due to a degraded pedestal performance and hence investigations at shifting the operational point to higher β N by lowering the current have been started. At higher q 95 , pedestal performance can be recovered by seeding N 2 as well as CD 4 , which is interpreted as improved pedestal stability due to the decrease of bootstrap current with increasing Z eff . Concerning advanced scenarios, the upgrade of ECRH power has allowed experiments with central ctr-ECCD to modify the q -profile in improved H-mode scenarios, showing an increase in confinement at still good MHD stability with flat elevated q -profiles at values between 1.5 and 2. European Commission (EUROfusion 633053)

Published
2015
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20. In-situ Low Power Tests of the ASDEX Upgrade ECRH Transmission Lines

Author

Wagner Dietmar, Leuterer Fritz, Monaco Francesco, Schütz Harald, Stober Jörg, and Thumm Manfred

Subjects
Physics, QC1-999
Abstract

An Electron Cyclotron Resonance Heating (ECRH) system employing 8 gyrotrons is in routine operation at the ASDEX Upgrade tokamak at IPP Garching. The gyrotrons are of two-frequency type operating at 105 and 140 GHz with a maximum output power of up to 1 MW and 10 s pulse length. The gyrotron output beams are coupled to 8 waveguide transmission lines via quasi-optical Matching Optics Units (MOUs). The oversized corrugated HE11 waveguides with a diameter of 87 mm are operated at atmospheric pressure with overall lengths between 65 and 103 meters. The number of quasi-optical miter bends per line is between 6 and 8. High mode purity in the transmission lines is critical with respect to both, losses and atmospheric breakdowns in the waveguides. Beam measurements at low power have been performed along the transmission lines and are compared to high power measurements. Near-field calculations and measurements of mm-wave beams radiated from open-ended HE11 waveguides show, that varying intensity patterns determine the distribution of Ohmic loading in compact mm-wave beam launching antennas, where the first mirror is located in the reactive near-field or close to the Fresnel maximum.

Published
2024
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21. High power ECRH and ECCD in moderately collisional ASDEX Upgrade H-modes and status of EC system upgrade

Author

Stober, J., Sommer, F., Angioni, C., Bock, A., Fable, E., Leuterer, F., Monaco, F., Müller, S., Münich, M., Petzold, B., Poli, E., Schubert, M., Schütz, H., Wagner, D., Zohm, H., ASDEX Upgrade Team, Kasparek, W., Plaum, B., Meier, A., Scherer, Th., Strauß, D., Jelonnek, J., Thumm, M., Litvak, A., Denisov, G.G., Chirkov, A.V., Tai, E.M., Popov, L.G., Nichiporenko, V.O., Myasnikov, V.E., Soluyanov, E.A., Malygin, V., and ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Tokamak, Chemistry, Physics, QC1-999, Electron, Plasma, Radius, law.invention, Ion, Upgrade, ASDEX Upgrade, law, Physics::Plasma Physics, Heat exchanger, Atomic physics, ddc:620, Engineering & allied operations
Abstract

This contribution deals with H-modes with significant heat exchange between electrons and ions, but which can still show large differences between electron and ion-temperatures especially inside half minor radius. These conditions are referred to as moderately collisional. A systematic study shows that an increasing fraction of electron heating increases the transport in the ion channel mainly due to the dependence of the ITG dominated ion transport on the ratio Te/Ti in agreement with modeling. The rotational shear in the plasmas under study was so small that it hardly influences ITG stability, such that variations of the rotation profile due to a change of the heating method were of minor importance. These findings connect to studies of advanced tokamak scenarios using ECCD as a tool to modify the q-profile. The electron heating connected to the ECCD tends to increase the transport in the ion channel quite in contrast to the goal to operate at reduced current but with increased confinement. The confinement only increases as the fraction of ion heating is increased by adding more NBI. An ITER case was modeled as well. Due to the larger value of νei ・ τE the ratio Te/Ti is only moderately reduced even with strong electron heating and the confinement reduction is small even for the hypothetic case of using only ECRH as additional heating. Finally the paper discusses the ongoing upgrade of the AUG ECRH-system.

Published
2015

22. Matched calorimetric loads for high power millimeter-wave gyrotrons

Author

Bruschi, A, Muzzini, V, Spinicchia, N, Benocci, R, Carcano, G, Cirant, S, Gandini, F, Gittini, G, Granucci, G, Leuterer, F, Mellera, V, Monaco, F, Muenich, M, Nardone, A, Schuetz, H, Signorelli, E, Simonetto, A, Sozzi, C, Bruschi A., Muzzini V., Spinicchia N., Benocci R., Carcano G., Cirant S., Gandini F., Gittini G., Granucci G., Leuterer F., Mellera V., Monaco F., Muenich M., Nardone A., Schuetz H., Signorelli E., Simonetto A., Sozzi C., Bruschi, A, Muzzini, V, Spinicchia, N, Benocci, R, Carcano, G, Cirant, S, Gandini, F, Gittini, G, Granucci, G, Leuterer, F, Mellera, V, Monaco, F, Muenich, M, Nardone, A, Schuetz, H, Signorelli, E, Simonetto, A, Sozzi, C, Bruschi A., Muzzini V., Spinicchia N., Benocci R., Carcano G., Cirant S., Gandini F., Gittini G., Granucci G., Leuterer F., Mellera V., Monaco F., Muenich M., Nardone A., Schuetz H., Signorelli E., Simonetto A., and Sozzi C.

Abstract

High power gyrotron testing at long pulses is a necessary step in the development of mm-wave systems for fusion research. For this purpose a compact calorimetric load is being developed, with low overall reflectivity (< 5%) and aiming at 1 MW-CW capabilities, after the good performances of the loads (0.5 MW, 0.5 s per pulse) installed on the 140 GHz ECRH plant of the FTU Tokamak in Frascati. Tests at the same frequency but at higher power (0.7 MW, 1 s) and longer pulses (up to 2 s at 0.5 MW) on the ASDEX-Upgrade ECRH plant showed, after repeated exposures, damages on the absorbing layer, recognized as thermal effects due to the local enhancement of incident power: the effects visible near the entrance port are explained studying the superposition (with interference) of waves reflected inside the sphere. Samples of degraded and non-degraded coating have been analyzed with various techniques, revealing changes of the substrate's physical characteristics. Measurements of absorber temperature during and after the pulse, performed with an infrared detector looking directly into the load, allowed estimates of the peak temperature and thermal properties of the coating in the real working conditions. Improvements on power deposition, geometry and cooling are proposed, to be integrated in a new load design. (C) 2003 Elsevier Science B.V. All rights reserved.

Published
2003

24. Comparison of fast ion collective Thomson scattering measurements at ASDEX Upgrade with numerical simulations

Author

Salewski, M., Meo, F., Stejner, M., Asunta, O., Bindslev, H., Furtula, V., Korsholm, S. B., Kurki-Suonio, T., Leipold, F., Leuterer, F., Michelsen, P. K., Moseev, D., Nielsen, S. K., Stober, J., Tardini, G., Wagner, D., Woskov, P., ASDEX Upgrade Team, and ASDEX Upgrade Team

Subjects
Physics, Nuclear and High Energy Physics, education.field_of_study, Thomson scattering, Population, Condensed Matter Physics, 01 natural sciences, Neutral beam injection, Fusionsenergiforskning, 010305 fluids & plasmas, Ion, Fusion energy, Fusionsenergi, Distribution function, ASDEX Upgrade, Physics::Plasma Physics, 0103 physical sciences, Plasma diagnostics, Atomic physics, 010306 general physics, education, Beam (structure)
Abstract

Collective Thomson scattering (CTS) experiments were carried out at ASDEX Upgrade to measure the one-dimensional velocity distribution functions of fast ion populations. These measurements are compared with simulations using the codes TRANSP/NUBEAM and ASCOT for two different neutral beam injection (NBI) configurations: two NBI sources and only one NBI source. The measured CTS spectra as well as the inferred one-dimensional fast ion velocity distribution functions are clearly asymmetric as a consequence of the anisotropy of the beam ion populations and the selected geometry of the experiment. As expected, the one-beam configuration can clearly be distinguished from the two-beam configuration. The fast ion population is smaller and the asymmetry is less pronounced for the one-beam configuration. Salient features of the numerical simulation results agree with the CTS measurements while quantitative discrepancies in absolute values and gradients are found.

Published
2010
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25. Axially Symmetric Divertor Experiment (ASDEX) Upgrade Team (vol 81, 033507, 2010)

Author

Adamek, J., Angioni, C., Antar, G., Atanasiu, C.V., Balden, M., Becker, W., Behler, K., Behringer, K., Bergmann, A., Bilato, R., Bobkov, V., Boom, J., Bottino, A., Brambilla, M., Braun, F., Brüdgam, M., Buhler, A., Chankin, A., Classen, I., Conway, G.D., Coster, D.P., de Marne, P., D'Inca, R., Dodt, D., Doerk-Bendig, H., Drube, R., Dux, R., Eich, T., Endstrasser, N., Engelhardt, K., Fahrbach, H.-U., Fattorini, L., Fischer, R., Forest, C., Fuchs, J.C., Gal, K., Munoz, M.G., Adamov, M.G., Giannone, L., Görler, L., Gori, S., da Graca, S., Greuner, H., Gruber, O., Gude, A., Günter, S., Haas, G., Hammer, N., Hauff, T., Heinemann, B., Herrmann, A., Hicks, N., Hobirk, J., Hölzl, M., Holtum, D., Hopf, C., Huart, M., Igochine, V., Janzer, M., Jenko, F., Kagarmanov, A., Kallenbach, A., Kammel, A., Kalvin, S., Kardaun, O., Kaufmann, M., Kick, M., Kirk, A., Klingshirn, H.-J., Koscis, G., Kollotzek, H., Konz, C., Krieger, K., Kurki-Suonio, T., Kurzan, B., Lackner, K., Lang, P.T., Langer, B., Lauber, P., Laux, M., Leuterer, F., Likonen, J., Liu, L., Lohs, A., Lunt, T., Lyssoivan, A., Mank, K., Manso, M.-E., Mantsinen, M., Maraschek, M., Martin, P., Mayer, M., McCarthy, P., McCormick, K., McDermott, R., Meister, H., Meo, Fernando, Merkel, P., Merkel, R., Mertens, V., Merz, F., Meyer, H., Mlynek, A., Monaco, F., Müller, H.-W., Münich, M., Murmann, H., Neu, G., Neu, R., Neuhauser, J., Nold, B., Noterdaeme, J.M., Pautasso, G., Pereverzev, G., Poli, E., Potzel, S., Püschel, M., Pütterich, T., Raupp, G., Reich, M., Reiter, B., Ribeiro, T., Riedl, R., Rohde, V., Roth, J., Rott, M., Ryter, F., Sandmann, W., Santos, J., Sassenberg, K., Sauter, P., Scarabosio, A., Schall, G., Schmid, K., Schneider, P., Schneider, W., Schrittwieser, R., Schweinzer, J., Scott, B., Seidel, U., Sempf, M., Serra, F., Sertoli, M., Siccinio, M., Sigalov, A., Silva, A., Speth, E., Stäbler, A., Stadler, R., Steuer, K.-H., Stober, J., Streibl, B., Strumberger, E., Suttrop, W., Tardini, G., Tichmann, C., Treutterer, W., Urso, L., Vainonen-Ahlgren, E., Varela, P., Vorpahl, C., Wagner, D., Wigger, C., Wischmeier, M., Wolfrum, E., Würsching, E., Yadikin, D., Yu, Q., Zasche, D., Zehetbauer, T., Zilker, M., and Zohm, H.

Subjects
Fusion energy, Fusionsenergi, Fusionsenergiforskning
Published
2010
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26. Spatially resolved fast ion velocity distribution results from on-axis and off-axis NBI heated plasmas on ASDEX Upgrade using the Collective Thomson Scattering (CTS)

Author

Fernando Meo, Mirko Salewski, Henrik Bindslev, Hobirk, J., Søren Bang Korsholm, Leuterer, F., Frank Leipold, Poul Michelsen, Dmitry Moseev, Garcia-Munoz, M., Stefan Kragh Nielsen, Morten Stejner Pedersen, Stober, J., Tardini, G., Wagner, D., and ASDEX Upgrade Team

Subjects
Fusion energy, Fusionsenergi, Fusionsenergiforskning
Published
2010

27. Overview of ASDEX upgrade results

Author

Zohm H., Adamek J., Angioni C., Antar G., Atanasiu C. V., Balden M., Becker W., Behler K., Behringer K., Bergmann A., Bertoncelli T., Bilato R., Bobkov V., Boom J., Bottino A., Brambilla M., Braun F., Bruedgam M., Buhler A., Chankin A., Classen I., Conway G. D., Coster D. P., de Marne P., D'Inca R., Drube R., Dux R., Eich T., Engelhardt K., Esposito B., Fahrbach H-U., Fattorini L., Fink J., Fischer R., Flaws A., Foley M., Forest C., Fuchs J. C., Gal K., Munoz M. Garcia, Adamov M. Gemisic, Giannone L., Goerler T., Gori S., da Graca S., Granucci G., Greuner H., Gruber O., Gude A., Guenter S., Haas G., Hahn D., Harhausen J., Hauff T., Heinemann B., Herrmann A., Hicks N., Hobirk J., Hoelzl M., Holtum D., Hopf C., Horton L., Huart M., Igochine V., Janzer M., Jenko F., Kallenbach A., Kalvin S., Kardaun O., Kaufmann M., Kick M., Kirk A., Klingshirn H-J., Koscis G., Kollotzek H., Konz C., Krieger K., Kurki-Suonio, Kurzan B., Lackner K., Lang P. T., Langer B., Lauber P., Laux M., Leuterer F., Likonen J., Liu L., Lohs A., Lunt T., Lyssoivan A., Maggi C. F., Manini A., Mank K., Manso M-E., Mantsinen M., Maraschek M., Martin P., Mayer M., McCarthy P., McCormick K., Meister H., Meo F., Merkel P., Merkel R., Mertens V., Merz F., Meyer H., Mlynek A., Monaco F., Mueller H-W., Muenich M., Murmann H., Neu G., Neu R., Neuhauser J., Nold B., Noterdaeme J-M., Pautasso G., Pereverzev G., Poli E., Potzel, Pueschel M., Puetterich T., Pugno R., Raupp G., Reich M., Reiter B., Ribeiro T., Riedl R., Rohde V., Roth J., Rott M., Ryter F., Sandmann W., Santos J., Sassenberg, Sauter P., Scarabosio A., Schall G., Schilling H-B., Schirmer J., Schmid A., Schmid K., Schneider W., Schramm G., Schrittwieser R., Schustereder W., Schweinzer J., Schweizer S., Scott B., Seidel U., Sempf M., Serra F., Sertoli M., Siccinio M., Sigalov A., Silva A., Sips C. C., Speth E., Staebler A., Stadler R., Steuer K-H., Stober J., Streibl B., Strumberger E., Suttrop W., Tardini G., Tichmann C., Treutterer W., Troester C., Urso L., Vainonen-Ahlgren E., Varela P., Vermare L., Volpe F., Wagner D., Wigger C., Wischmeier M., Wolfrum E., Wuersching E., Yadikin D., Yu Q., Zasche D., Zehetbauer T., and Zilker M.

Subjects
Nuclear and High Energy Physics, Materials science, Nuclear engineering, Condensed Matter Physics, 7. Clean energy, 01 natural sciences, 010305 fluids & plasmas, ASDEX Upgrade, ITER, 0103 physical sciences, tokamak physics, 010306 general physics, DEMO, nuclear fusion
Abstract

ASDEX Upgrade was operated with a fully W-covered wall in 2007 and 2008. Stationary H-modes at the ITER target values and improved H-modes with H up to 1.2 were run without any boronization. The boundary conditions set by the full W wall (high enough ELM frequency, high enough central heating and low enough power density arriving at the target plates) require significant scenario development, but will apply to ITER as well. D retention has been reduced and stationary operation with saturated wall conditions has been found. Concerning confinement, impurity ion transport across the pedestal is neoclassical, explaining the strong inward pinch of high-Z impurities in between ELMs. In improved H-mode, the width of the temperature pedestal increases with heating power, consistent with a β1/2pol,ped scaling. In the area of MHD instabilities, disruption mitigation experiments using massive Ne injection reach volume averaged values of the total electron density close to those required for runaway suppression in ITER. ECRH at the q = 2 surface was successfully applied to delay density limit disruptions. The characterization of fast particle losses due to MHD has shown the importance of different loss mechanisms for NTMs, TAEs and also beta-induced Alfven eigenmodes (BAEs). Specific studies addressing the first ITER operational phase show that O1 ECRH at the HFS assists reliable low-voltage breakdown. During ramp-up, additional heating can be used to vary li to fit within the ITER range. Confinement and power threshold in He are more favourable than in H, suggesting that He operation could allow us to assess H-mode operation in the non-nuclear phase of ITER operation.

Published
2009
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28. Recent upgrades and extensions of the new multi-frequency ECRH system at ASDEX upgrade

Author

Wagner, D., Stober, J., Bäumel, S., Franke, T., Leuterer, F., Monaco, F., Münich, M., Schmid-Lorch, D., Schütz, H., Zohm, H., Thumm, M., Scherer, T., Meier, A., Gantenbein, G., Flamm, J., Kasparek, W., Höhnle, H., Lechte, C., Litvak, A. G., Denisov, G. G., Cirkov, A., Tai, E. M., Popov, L. G., Nichiporenko, V. O., Myasnikov, V. E., Solyanova, E. A., and Malygin, S. A.

Subjects
ddc:620, Engineering & allied operations
Published
2009
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29. Commissioning activities and first results from the collective Thomson scattering diagnostic on ASDEX Upgrade (invited)

Author

Meo, Fernando, Bindslev, Henrik, Korsholm, Søren Bang, Furtula, Vedran, Leuterer, F., Leipold, Frank, Michelsen, Poul, Nielsen, Stefan Kragh, Salewski, Mirko, Stober, J., Wagner, D., and Woskov, P.

Subjects
Physics::Plasma Physics, Energiteknologier på vej
Abstract

The collective Thomson scattering (CTS) diagnostic installed on ASDEX Upgrade uses millimeter waves generated by the newly installed 1 MW dual frequency gyrotron as probing radiation at 105 GHz. It measures backscattered radiation with a heterodyne receiver having 50 channels (between 100 and 110 GHz) to resolve the one-dimensional velocity distribution of the confined fast ions. The steerable antennas will allow different scattering geometries to fully explore the anisotropic fast ion distributions at different spatial locations. This paper covers the capabilities and operational limits of the diagnostic. It then describes the commissioning activities carried out to date. These activities include gyrotron studies, transmission line alignment, and beam pattern measurements in the vacuum vessel. Overlap experiments in near perpendicular and near parallel have confirmed the successful alignment of the system. First results in near perpendicular of scattered spectra in a neutral beam injection (NBI) and ion cyclotron resonance heating (ICRH) plasma (minority hydrogen) on ASDEX Upgrade have shown evidence of ICRH heating phase of hydrogen. ©2008 American Institute of Physics

Published
2008
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34. New frequency step tunable ECRH system for ASDEX Upgrade

Author

Wagner, D., Leuterer, F., Manini, A., Monaco, F., Münich, M., Ryter, F., Schütz, H., Zohm, H., Franke, T., Heidinger, R., Thumm, M., Kasparek, W., Gantenbein, G., Litvak, A. G., Popov, L. G., Nichiporenko, V. O., Myasnikov, V. E., Denisov, G. G., Tai, E. M., Solyanova, E. A., and Malygin, S. A.

Published
2006

41. Status of the New ECRH System for ASDEX Upgrade

Author

Wagner, D., Grünwald, G., Leuterer, F., Monaco, F., Münich, M., Schütz, H., Ryter, F., Wilhelm, R., Zohm, H., Franke, T., Dammertz, G., Heidinger, H., Koppenburg, K., Thumm, M., Yang, X., Kasparek, W., Gantenbein, G., Hailer, H., Denisov, G., Litvak, A., and Zapevalov, V.

Published
2004

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