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1. Overview of the first Wendelstein 7-X long pulse campaign with fully water-cooled plasma facing components

Author

O. Grulke, C. Albert, J.A. Alcuson Belloso, P. Aleynikov, K. Aleynikova, A. Alonso, G. Anda, T. Andreeva, M. Arvanitou, E. Ascasibar, E. Aymerich, K. Avramidis, J.-P. Bähner, S.-G. Baek, M. Balden, J. Baldzuhn, S. Ballinger, M. Banduch, S. Bannmann, A. Bañón Navarro, L. Baylor, C.D. Beidler, M. Beurskens, C. Biedermann, G. Birkenmeier, T. Bluhm, D. Boeckenhoff, D. Boeyaert, D. Bold, M. Borchardt, D. Borodin, H.-S. Bosch, H. Bouvain, S. Bozhenkov, T. Bräuer, H. Braune, C. Brandt, S. Brezinsek, K.J. Brunner, C. Büschel, R. Bussiahn, A. Buzás, B. Buttenschoen, V. Bykov, I. Calvo, A. Cappa, F. Carovani, D. Carralero, A. Carls, B. Carvalho, D. Castaño-Bardawil, N. Chaudhary, I. Chelis, S. Chen, D. Cipciar, J.W. Coenen, G. Conway, M. Cornelissen, Y. Corre, P. Costello, K. Crombe, G. Cseh, B. Csillag, H.I. Cu Castillo, G. Czymek, H. Damm, R.J. Davies, C. Day, S. Degenkolbe, R. De Wolf, W. Dekeyser, A. Demby, P. Despontin, C.P. Dhard, A. Dinklage, F.A. d’Isa, T. Dittmar, M. Dreval, M. Drevlak, P. Drews, J. Droste, D. Dunai, C. Dyhring, P. van Eeten, E. Edlund, M. Endler, D.A. Ennis, F.J. Escoto, M.S. Espinosa, T. Estrada, D. Fehling, L. Feuerstein, J. Fellinger, Y. Feng, D.L.C. Fernando, S. Fischer, E.R. Flom, O. Ford, T. Fornal, J. Frank, H. Frerichs, G. Fuchert, G. Gantenbein, Y. Gao, K. Garcia, I. García-Cortés, J.M. García-Regaña, B. Geiger, J. Geiger, P. Geissler, M. Gerard, G. Godino-Sedano, T. Gonda, A. González, A. Goriaev, D. Gradic, M. Grahl, H. Greuner, E. Grigore, M. Gruca, J.F. Guerrero Arnaiz, V. Haak, L. van Ham, K. Hammond, B. Hamstra, X. Han, S.K. Hansen, J. Harris, D. Hartmann, D. Hathiramani, S. Hegedus, S. Heinrich, P. Helander, F. Henke, S. Henneberg, L. Henschke, M. Hirsch, U. Hoefel, K. Hoefler, S. Hoermann, K.-P. Hollfeld, A. Holtz, D. Höschen, M. Houry, J. Huang, M. Hubeny, K. Hunger, D. Hwangbo, K. Ida, Y. Igitkhanov, S. Illy, Z. Ioannidis, M. Jablczynska, S. Jablonski, B. Jabłoński, B. Jagielski, M. Jakubowski, J. Jelonnek, F. Jenko, J. Jin, A. Johansson, G. Jouniaux, S. Kajita, J.-P. Kallmeyer, U. Kamionka, W. Kasparek, C. Kawan, Ye. O. Kazakov, N. Kenmochi, W. Kernbichler, A.K. Kharwandikar, M. Khokhlov, C. Killer, A. Kirschner, R. Kleiber, C.C. Klepper, T. Klinger, J. Knauer, A. Knieps, M. Kobayashi, G. Kocsis, Y. Kolesnichenko, A. Könies, J. Kontula, P. Kornejew, S.A. Korteweg, J. Koschinsky, J. Koster, Y. Kovtun, A. Krämer-Flecken, M. Krause, T. Kremeyer, L. Krier, D.M. Kriete, M. Krychowiak, I. Ksia¸zek, M. Kubkowska, M.D. Kuczyński, D. Kulla, A. Kumar, T. Kurki-Suonio, I. Kuzmych, S. Kwak, V. Lancelotti, A. Langenberg, H. Laqua, H.P. Laqua, M.R. Larsen, S. Lazerson, C. Lechte, B. Lee, A. LeViness, M. Lewerentz, Y. Liang, L. Liao, A. Litnovsky, J. Liu, J. Loizu, R. Lopez-Cansino, L.D. Lopez Rodriguez, A. Lorenz, R. Lunsford, Y. Luo, V. Lutsenko, N. Maaziz, M. Machielsen, R. Mackenbach, D. Makowski, E. Maragkoudakis, O. Marchuk, M. Markl, S. Marsen, J. Martínez, N. Marushchenko, S. Masuzaki, D.A. Maurer, M. Mayer, K.J. McCarthy, P. McNeely, D. Medina Roque, J. Meineke, S. Meitner, S. vaz Mendes, A. Menzel-Barbara, B. van Milligen, A. Mishchenko, V. Moiseenko, A. Möller, S. Möller, D. Moseev, G. Motojima, S. Mulas, P. Mulholland, M. Nagel, D. Nagy, Y. Narbutt, D. Naujoks, P. Nelde, R. Neu, O. Neubauer, U. Neuner, D. Nicolai, S. Nielsen, C. Nührenberg, R. Ochoukov, G. Offermanns, J. Ongena, J.W. Oosterbeek, M. Otte, N. Pablant, N. Panadero Alvarez, A. Pandey, G. Partesotti, E.A. Pasch, R. Pavlichenko, E. Pawelec, T.S. Pedersen, V. Perseo, B. Peterson, F. Pisano, B. Plaum, G. Plunk, L. Podavini, N.S. Polei, P. Poloskei, S. Ponomarenko, P. Pons-Villalonga, M. Porkolab, J. Proll, M.J. Pueschel, A. Puig Sitjes, R. Ragona, K. Rahbarnia, M. Rasiński, J. Rasmussen, D. Refy, F. Reimold, M. Richou, J.S. Riemann, K. Riße, J. de la Riva Villén, G. Roberg-Clark, E. Rodriguez, V. Rohde, J. Romazanov, T. Romba, D. Rondeshagen, M. Rud, T. Ruess, T. Rummel, A. Runov, C. Ruset, N. Rust, L. Ryc, T. Rzesnicki, M. Salewski, E. Sánchez, L. Sanchis Sanchez, G. Satheeswaran, J. Schacht, E. Scharff, J. Schilling, G. Schlisio, K. Schmid, J.C. Schmitt, O. Schmitz, M. Schneider, M. Van Schoor, T. Schröder, R. Schroeder, B. Schweer, S. Sereda, B. Shanahan, G. Sias, S. Simko, L. Singh, Y. Siusko, C. Slaby, M. Śle¸czka, B.S. Smith, D.R. Smith, H. Smith, M. Spolaore, A. Spring, T. Stange, A. von Stechow, I. Stepanov, M. Stern, U. Stroth, Y. Suzuki, C. Swee, L. Syrocki, T. Szabolics, T. Szepesi, R. Takacs, H. Takahashi, N. Tamura, C. Tantos, J. Terry, S. Thiede, H. Thienpondt, H. Thomsen, M. Thumm, T. Thun, S. Togo, T. Tork, H. Trimino Mora, A. Tsikouras, Y. Turkin, L. Vano, S. Varoutis, M. Vecsei, J.L. Velasco, M. Verstraeten, M. Vervier, E. Viezzer, J. Wagner, E. Wang, F. Wang, M. Wappl, F. Warmer, T. Wegner, Y. Wei, G. Weir, N. Wendler, U. Wenzel, A. White, F. Wilms, T. Windisch, A. Winter, V. Winters, R. Wolf, G. Wurden, P. Xanthopoulos, H.M. Xiang, S. Xu, H. Yamada, J. Yang, R. Yi, M. Yokoyama, B. Zamorski, M. Zanini, M. Zarnstorff, D. Zhang, S. Zhou, J. Zhu, J. Zimmermann, A. Zocco, and S. Zoletnik more...

Subjects
stellarator, long-pulse operation, magnetic fusion confinement, divertor detachment, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

After a long device enhancement phase, scientific operation resumed in 2022. The main new device components are the water cooling of all plasma facing components and the new water-cooled high heat flux divertor units. Water cooling allowed for the first long-pulse operation campaign. A maximum discharge length of 8 min was achieved with a total heating energy of 1.3 GJ. Safe divertor operation was demonstrated in attached and detached mode. Stable detachment is readily achieved in some magnetic configurations but requires impurity seeding in configurations with small magnetic pitch angle within the edge islands. Progress was made in the characterization of transport mechanisms across edge magnetic islands: Measurement of the potential distribution and flow pattern reveals that the islands are associated with a strong poloidal drift, which leads to rapid convection of energy and particles from the last closed flux surface into the scrape-off layer. Using the upgraded plasma heating systems, advanced heating scenarios were developed, which provide improved energy confinement comparable to the scenario, in which the record triple product for stellarators was achieved in the previous operation campaign. However, a magnetic configuration-dependent critical heating power limit of the electron cyclotron resonance heating was observed. Exceeding the respective power limit leads to a degradation of the confinement. more...

Published
2024
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2. Long plasma duration operation analyses with an international multi-machine (tokamaks and stellarators) database

Author

X. Litaudon, H.-S. Bosch, T. Morisaki, M. Barbarino, A. Bock, E. Belonohy, S. Brezinsek, J. Bucalossi, S. Coda, R. Daniel, A. Ekedahl, K. Hanada, C. Holcomb, J. Huang, S. Ide, M. Jakubowski, B. V. Kuteev, E. Lerche, T. Luce, P. Maget, Y. Song, J. Stober, D. VAN Houtte, Y. Xi, L. Xue, S. Yoon, B. Zhang, and JET contributors more...

Subjects
nuclear fusion, long plasma duration operation, international multi-machine (tokamaks and stellarators) database, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Combined high-fusion performance and long-pulse operation is one of the key integration challenges for fusion energy development in magnetic devices. Addressing these challenges requires an integrated vision of physics and engineering aspects with the purpose of simultaneously increasing time duration and fusion performance. Significant progress has been made in tokamaks and stellarators, including very recent achievement in duration and/or performance. This progress is reviewed by analyzing the experimental data (109 plasma pulses with a total of 3200 data points, i.e. on average 29 data per pulse) provided by ten tokamaks (in alphabetical order: Axially Symmetric Divertor Experiment Upgrade, DIII-D, Experimental Advanced Superconducting Tokamak, Joint European Torus, JT-60 Upgrade, Korea Superconducting Tokamak Advanced Research, tokamak à configuration variable, Tokamak Fusion Test Reactor, Tore Supra, W Environment in Steady-State Tokamak) and two stellarators (Large Helical Device and Wendelstein 7-X) expanding the pioneering work of Kikuchi (Kikuchi M. and Azumi M. 2015 Frontiers in Fusion Research II: Introduction to Modern Tokamak Physics (Springer)). Data have been gathered up to January 2022 and coordination has been provided by the recently created International Energy Agency-International Atomic Energy Agency international C oordination on I nternational C hallenges on L ong duration OP eration group. By exploiting the multi-machine international database, recent progress in terms of injected energies (e.g. 1730 MJ in L-mode, 425 MJ in H-mode), durations (1056 s in L-mode, 101 s in H-mode), injected powers, and sustained performance will be reviewed. Progress has been made to sustain long-pulse operation in tokamaks and stellarators with superconducting coils, actively cooled components, and/or with metallic walls. The graph of the fusion triple products as a function of duration shows a dramatic reduction of, at least two orders of magnitude when increasing the plasma duration from less than 1 s to 100 s. Indeed, long-pulse operation is usually reached in dominant electron-heating modes at reduced density (current drive optimization) but with low ion temperatures ranging from 1 to 3 keV for discharges above 100 s. Difficulties in extending the duration may arise from coupling high heating powers over long durations and the evolving plasma-wall interaction towards an unstable operational domain. Possible causes limiting the duration and critical issues to be addressed prior to ITER operation and DEMO design are reported and analyzed. more...

Published
2023
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5. Confirmation of the topology of the Wendelstein 7-X magnetic field to better than 1:100,000

Author

T. Sunn Pedersen, M. Otte, S. Lazerson, P. Helander, S. Bozhenkov, C. Biedermann, T. Klinger, R. C. Wolf, H. -S. Bosch, and The Wendelstein 7-X Team

Subjects
Science
Abstract

Early stellarator designs suffered from high particle losses, an issue that can be addressed by optimization of the coils. Here the authors measure the magnetic field lines in the Wendelstein 7-X stellarator, confirming that the complicated design of the superconducting coils has been realized successfully. more...

Published
2016
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7. Erratum: Confirmation of the topology of the Wendelstein 7-X magnetic field to better than 1:100,000

Author

T. Sunn Pedersen, M. Otte, S. Lazerson, P. Helander, S. Bozhenkov, C. Biedermann, T. Klinger, R. C. Wolf, H-S Bosch, and The Wendelstein 7-X Team

Subjects
Science
Abstract

Nature Communications 7: Article number: 13493 (2016); Published: 30 November 2016; Updated: 14 February 2017 The original version of this Article contained errors in the spelling of authors names and their affiliations. These errors were: The affiliation of Boyd Blackwell is 10, but was incorrectlygiven as 10,11,12. more...

Published
2017
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8. The new W7-X logbook – A software for effective experiment documentation and collaborative research at Wendelstein 7-X

Author

H. P. Laqua, Torsten Bluhm, M. Grahl, H.-S. Bosch, Marc Lewerentz, R. Brakel, M. Hirsch, Anett Spring, A. Werner, M. Grün, S. Dumke, A. Holtz, P. van Eeten, H. Riemann, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society more...

Subjects
Web browser, Database, business.industry, Computer science, Mechanical Engineering, computer.software_genre, 01 natural sciences, 010305 fluids & plasmas, Documentation, Software, Nuclear Energy and Engineering, Component (UML), 0103 physical sciences, Web page, General Materials Science, Use case, Wendelstein 7-X, 010306 general physics, business, Logbook, computer, Civil and Structural Engineering
Abstract

Wendelstein 7-X (W7-X) completed its second operation phase in December 2017. A large number of diagnostics were operated in nearly 1000 experiment programs (XP) by an international research team. For the documentation of W7-X XPs, a new electronic logbook software has been developed. The software has been designed for the needs of W7-X researchers and engineers: a web-based logbook application for the entire team. For an effective documentation, large parts of the logbook content comes from automatically generated logs, complemented by the team members via web browser or REST API. The W7-X control software generates log entries for an XP during program execution. This includes automatic extraction of configuration information from the planned program, which is later represented as searchable tags within the logbook. In addition, users can add supplementary tags and rich-text comments to all logs. The logbook allows full-text search and range queries for numeric values: both with millisecond response times. A dedicated web page for each XP log contains overview plots from measurement data, generated on the fly from archived data. Separate component logs are created in the same way for diagnostics and machine sub-systems for different use cases, e.g., XPs, standalone tests, or calibrations. The logbook hosts separate pages for device operation and the W7-X components, providing status information and additional features. In this way it effectively supports the operation of W7-X. more...

Published
2019
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9. Progress, Challenges, and Lessons Learned in the Construction of Wendelstein 7-X

Author

H.-S. Bosch, T. Bräuer, and Thomas Klinger

Subjects
Nuclear and High Energy Physics, Engineering, business.industry, law, Stellarator, Wendelstein 7-X, assembly, component alignment, metrology, mock-up, Electrical engineering, Systems engineering, Wendelstein 7-X, Fusion power, Condensed Matter Physics, business, Stellarator, law.invention
Abstract

This paper reports on experiences gained during the construction of the large superconducting optimized stellarator device Wendelstein 7-X (W7-X). The goal of the project is to demonstrate the fusion reactor potential of optimized stellarators and to operate for the first time fusion-relevant plasmas under full steady-state conditions. In addition, the validity of the engineering concept is to be proven under operating conditions. The actual construction of the device is now running since more than ten years and will require about three further years of assembly and integration. The current technical status of W7-X is reviewed, the major construction challenges are highlighted, and conclusions are drawn from past experiences that may also be useful for other large-scale science projects. more...

Published
2012
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10. Numerical modelling at the transition from W7-X construction to operation

Author

Tamara Andreeva, H.-S. Bosch, Joris Fellinger, L. Wegener, P. van Eeten, Martin Köppen, V. Bykov, Felix Schauer, and A. Carls

Subjects
Engineering, Field (physics), business.industry, Project commissioning, Numerical analysis, Mechanical engineering, Superconducting magnet, Modular design, Finite element method, law.invention, Max planck institute, law, business, Stellarator
Abstract

The Wendelstein 7-X modular advanced stellarator is in the commissioning phase at the Max Planck Institute for Plasma Physics in Greifswald, Germany. The focus of the numerical analysis has been shifted from support of the machine design and assembly towards preparation of commissioning steps, assessment of possible field disturbances under operational loads, and exploration of operational limits. more...

Published
2015

11. Overview of ASDEX Upgrade results

Author

O. Gruber, R. Arslanbekov, C. Atanasiu, A. Bard, G. Becker, W. Becker, M. Beckmann, K. Behler, K. Behringer, A. Bergmann, R. Bilato, D. Bolshukin, K. Borrass, H.-S. Bosch, B. Braams, M. Brambilla, R. Brandenburg, F. Braun, H. Brinkschulte, R. Brückner, B. Brüsehaber, K. Büchl, A. Buhler, H. Bürbaumer, A. Carlson, M. Ciric, G. Conway, D.P. Coster, C. Dorn, R. Drube, R. Dux, S. Egorov, W. Engelhardt, H.-U. Fahrbach, U. Fantz, H. Faugel, M. Foley, P. Franzen, P. Fu, J.C. Fuchs, J. Gafert, G. Gantenbein, O. Gehre, A. Geier, J. Gernhardt, E. Gubanka, A. Gude, S. Günter, G. Haas, D. Hartmann, B. Heinemann, A. Herrmann, J. Hobirk, F. Hofmeister, H. Hohenöcker, L. Horton, L. Hu, D. Jacobi, M. Jakobi, F. Jenko, A. Kallenbach, O. Kardaun, M. Kaufmann, A. Kendl, J.-W. Kim, K. Kirov, R. Kochergov, H. Kollotzek, W. Kraus, K. Krieger, B. Kurzan, G. Kyriakakis, K. Lackner, P.T. Lang, R.S. Lang, M. Laux, L. Lengyel, F. Leuterer, A. Lorenz, H. Maier, K. Mank, M.-E. Manso, M. Maraschek, K.-F. Mast, P.J. McCarthy, D. Meisel, H. Meister, F. Meo, R. Merkel, V. Mertens, J.P. Meskat, R. Monk, H.W. Müller, M. Münich, H. Murmann, G. Neu, R. Neu, J. Neuhauser, J.-M. Noterdaeme, I. Nunes, G. Pautasso, A.G. Peeters, G. Pereverzev, S. Pinches, E. Poli, R. Pugno, G. Raupp, T. Ribeiro, R. Riedl, S. Riondato, V. Rohde, H. Röhr, J. Roth, F. Ryter, H. Salzmann, W. Sandmann, S. Sarelma, S. Schade, H.-B. Schilling, D. Schlögl, K. Schmidtmann, R. Schneider, W. Schneider, G. Schramm, J. Schweinzer, S. Schweizer, B.D. Scott, U. Seidel, F. Serra, S. Sesnic, C. Sihler, A. Silva, A. Sips, E. Speth, A. Stäbler, K.-H. Steuer, J. Stober, B. Streibl, E. Strumberger, W. Suttrop, A. Tabasso, A. Tanga, G. Tardini, C. Tichmann, W. Treutterer, M. Troppmann, N. Tsois, W. Ullrich, M. Ulrich, P. Varela, O. Vollmer, U. Wenzel, F. Wesner, R. Wolf, E. Wolfrum, R. Wunderlich, N. Xantopoulos, Q. Yu, M. Zarrabian, D. Zasche, T. Zehetbauer, H.-P. Zehrfeld, A. Zeiler, and H. Zohm more...

Subjects
Nuclear and High Energy Physics, 0103 physical sciences, 010306 general physics, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas
Published
2001
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12. B2–EIRENE modelling of He compression and enrichment

Author

W. Ullrich, H.-S. Bosch, D. P. Coster, and ASDEX Upgrade Team

Subjects
Nuclear and High Energy Physics, Tokamak, Hydrogen, Chemistry, Divertor, chemistry.chemical_element, Plasma, Fusion power, law.invention, Nuclear Energy and Engineering, ASDEX Upgrade, Deuterium, Physics::Plasma Physics, law, Physics::Atomic and Molecular Clusters, General Materials Science, Physics::Atomic Physics, Atomic physics, Helium
Abstract

Helium compression and helium enrichment are important for most future fusion reactors since the He ash produced by the nuclear reactions needs to be pumped out to prevent its accumulation in the core of the plasma. (Helium compression is the ratio of the helium density in the pumping plenum to the helium density in the plasma; helium enrichment is the ratio of the helium compression to the hydrogen or deuterium compression.) In this work the B2–EIRENE code is used to model helium compression and enrichment on ASDEX Upgrade with divertor II under a variety of plasma densities, input powers, transport coefficients and divertor geometries so as to determine the range of acceptable operating conditions for effective He removal. A broad range of acceptable plasma conditions is found, though a lower limit of the upstream separatrix density is noted. more...

Published
2001
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13. Overview of ASDEX Upgrade results

Author

O Gruber, H.-S Bosch, S Günter, A Herrmann, A Kallenbach, M Kaufmann, K Krieger, K Lackner, V Mertens, R Neu, F Ryter, J Schweinzer, A Stäbler, W Suttrop, R Wolf, K Asmussen, A Bard, G Becker, K Behler, K Behringer, A Bergmann, M Bessenrodt-Weberpals, K Borrass, B Braams, M Brambilla, R Brandenburg, F Braun, H Brinkschulte, R Brückner, B Brüsehaber, K Büchl, A Buhler, H.P Callaghan, A Carlson, D.P Coster, L Cupido, S. de Peña Hempel, C Dorn, R Drube, R Dux, S Egorov, W Engelhardt, H.-U Fahrbach, U Fantz, H.-U Feist, P Franzen, J.C Fuchs, G Fussmann, J Gafert, G Gantenbein, O Gehre, A Geier, J Gernhardt, E Gubanka, A Gude, G Haas, K Hallatschek, D Hartmann, B Heinemann, G Herppich, W Herrmann, F Hofmeister, E Holzhauer, D Jacobi, M Kakoulidis, N Karakatsanis, O Kardaun, A Khutoretski, H Kollotzek, S Kötterl, W Kraus, B Kurzan, G Kyriakakis, P.T Lang, R.S Lang, M Laux, L.L Lengyel, F Leuterer, A Lorenz, H Maier, M Manso, M Maraschek, M Markoulaki, K.-F Mast, P.J McCarthy, D Meisel, H Meister, R Merkel, J.P Meskat, H.W Müller, M Münich, H Murmann, B Napiontek, G Neu, J Neuhauser, M Niethammer, J.-M Noterdaeme, G Pautasso, A.G Peeters, G Pereverzev, S Pinches, G Raupp, K Reinmüller, R Riedl, V Rohde, H Röhr, J Roth, H Salzmann, W Sandmann, H.-B Schilling, D Schlögl, K Schmidtmann, H Schneider, R Schneider, W Schneider, G Schramm, S Schweizer, R.R Schwörer, B.D Scott, U Seidel, F Serra, S Sesnic, C Sihler, A Silva, E Speth, K.-H Steuer, J Stober, B Streibl, A Thoma, W Treutterer, M Troppmann, N Tsois, W Ullrich, M Ulrich, P Varela, H Verbeek, O Vollmer, H Wedler, M Weinlich, U Wenzel, F Wesner, R Wunderlich, N Xantopoulos, Q Yu, D Zasche, T Zehetbauer, H.-P Zehrfeld, H Zohm, and M Zouhar more...

Subjects
Nuclear and High Energy Physics, 0103 physical sciences, 010306 general physics, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas
Published
1999
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14. Preparation of the Wendelstein 7-X commissioning

Author

H.-S. Bosch, R. Brakel, M. Gasparotto, D. Hartmann, Dirk Naujoks, and R. Herrmann

Subjects
Physics, law, Project commissioning, Nuclear engineering, Wendelstein 7-X, Stellarator, law.invention
Abstract

Assembly of the superconducting stellarator Wendelstein 7-X is well advanced, and commissioning of the device is being prepared. A first draft of the commissioning tasks has been developed and will be discussed in this paper. more...

Published
2013
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15. Invariance of Divertor Retention on External Particle Flow in Detached ASDEX Upgrade Discharges

Author

H.-S. Bosch, R. Dux, G. Haas, A. Kallenbach, M. Kaufmann, K. Lackner, V. Mertens, H.-D. Murmann, W. Poschenrieder, H. Salzmann, J. Schweinzer, W. Suttrop, M. Weinlich, null ASDEX Upgrade team, null NI team, ASDEX Upgrade Team, and NI Team more...

Subjects
Physics, Nuclear physics, ASDEX Upgrade, Physics::Plasma Physics, Impurity, Divertor, General Physics and Astronomy, Gas flux, Particle flow, Plasma, Decoupling (cosmology), Atomic physics, Astrophysics::Galaxy Astrophysics
Abstract

Divertor plasmas with strong external gas puffing in ASDEX Upgrade have shown very efficient impurity retention, increasing with the divertor neutral gas density. The experiments presented here use feedback-controlled gas puffs in discharges with different pumping speed to keep the divertor neutral gas flux density the same. This allows for the first time a decoupling of the divertor neutral gas flux density and the external gas flow. The resulting plasmas are almost identical and show identical impurity retention, clearly demonstrating the importance of the divertor neutral gas density over the externally induced flow. {copyright} {ital 1996 The American Physical Society.} more...

Published
1996
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16. Technical challenges in the construction of the steady-state stellarator Wendelstein 7-X

Author

H.-S. Bosch, R.C. Wolf, T. Andreeva, J. Baldzuhn, D. Birus, T. Bluhm, T. Bräuer, H. Braune, V. Bykov, A. Cardella, F. Durodié, M. Endler, V. Erckmann, G. Gantenbein, D. Hartmann, D. Hathiramani, P. Heimann, B. Heinemann, C. Hennig, M. Hirsch, D. Holtum, J. Jagielski, J. Jelonnek, W. Kasparek, T. Klinger, R. König, P. Kornejew, H. Kroiss, J.G. Krom, G. Kühner, H. Laqua, H.P. Laqua, C. Lechte, M. Lewerentz, J. Maier, P. McNeely, A. Messiaen, G. Michel, J. Ongena, A. Peacock, T.S. Pedersen, R. Riedl, H. Riemann, P. Rong, N. Rust, J. Schacht, F. Schauer, R. Schroeder, B. Schweer, A. Spring, A. Stäbler, M. Thumm, Y. Turkin, L. Wegener, A. Werner, D. Zhang, M. Zilker, T. Akijama, R. Alzbutas, E. Ascasibar, M. Balden, M. Banduch, Ch. Baylard, W. Behr, C. Beidler, A. Benndorf, T. Bergmann, C. Biedermann, B. Bieg, W. Biel, M. Borchardt, G. Borowitz, V. Borsuk, S. Bozhenkov, R. Brakel, H. Brand, T. Brown, B. Brucker, R. Burhenn, K.-P. Buscher, C. Caldwell-Nichols, A. Cappa, A. Carls, P. Carvalho, Ł. Ciupiński, M. Cole, J. Collienne, A. Czarnecka, G. Czymek, G. Dammertz, C.P. Dhard, V.I. Davydenko, A. Dinklage, M. Drevlak, S. Drotziger, A. Dudek, P. Dumortier, G. Dundulis, P.v. Eeten, K. Egorov, T. Estrada, H. Faugel, J. Fellinger, Y. Feng, H. Fernandes, W.H. Fietz, W. Figacz, F. Fischer, J. Fontdecaba, A. Freund, T. Funaba, H. Fünfgelder, A. Galkowski, D. Gates, L. Giannone, J.M. García Regaña, J. Geiger, S. Geißler, H. Greuner, M. Grahl, S. Groß, A. Grosman, H. Grote, O. Grulke, M. Haas, L. Haiduk, H.-J. Hartfuß, J.H. Harris, D. Haus, B. Hein, P. Heitzenroeder, P. Helander, R. Heller, C. Hidalgo, D. Hildebrandt, H. Höhnle, A. Holtz, E. Holzhauer, R. Holzthüm, A. Huber, H. Hunger, F. Hurd, M. Ihrke, S. Illy, A. Ivanov, S. Jablonski, N. Jaksic, M. Jakubowski, R. Jaspers, H. Jensen, H. Jenzsch, J. Kacmarczyk, T. Kaliatk, J. Kallmeyer, U. Kamionka, R. Karaleviciu, S. Kern, M. Keunecke, R. Kleiber, J. Knauer, R. Koch, G. Kocsis, A. Könies, M. Köppen, R. Koslowski, J. Koshurinov, A. Krämer-Flecken, R. Krampitz, Y. Kravtsov, M. Krychowiak, G. Krzesinski, I. Ksiazek, M. Kubkowska, A. Kus, S. Langish, R. Laube, M. Laux, S. Lazerson, M. Lennartz, C. Li, R. Lietzow, A. Lohs, A. Lorenz, F. Louche, L. Lubyako, A. Lumsdaine, A. Lyssoivan, H. Maaßberg, P. Marek, C. Martens, N. Marushchenko, M. Mayer, B. Mendelevitch, Ph. Mertens, D. Mikkelsen, A. Mishchenko, B. Missal, T. Mizuuchi, H. Modrow, T. Mönnich, T. Morizaki, S. Murakami, F. Musielok, M. Nagel, D. Naujoks, H. Neilson, O. Neubauer, U. Neuner, R. Nocentini, J.-M. Noterdaeme, C. Nührenberg, S. Obermayer, G. Offermanns, H. Oosterbeek, M. Otte, A. Panin, M. Pap, S. Paquay, E. Pasch, X. Peng, S. Petrov, D. Pilopp, H. Pirsch, B. Plaum, F. Pompon, M. Povilaitis, J. Preinhaelter, O. Prinz, F. Purps, T. Rajna, S. Récsei, A. Reiman, D. Reiter, J. Remmel, S. Renard, V. Rhode, J. Riemann, S. Rimkevicius, K. Riße, A. Rodatos, I. Rodin, M. Romé, H.-J. Roscher, K. Rummel, Th. Rummel, A. Runov, L. Ryc, J. Sachtleben, A. Samartsev, M. Sanchez, F. Sano, A. Scarabosio, M. Schmid, H. Schmitz, O. Schmitz, M. Schneider, W. Schneider, L. Scheibl, M. Scholz, G. Schröder, M. Schröder, J. Schruff, H. Schumacher, I.V. Shikhovtsev, M. Shoji, G. Siegl, J. Skodzik, M. Smirnow, E. Speth, D.A. Spong, R. Stadler, Z. Sulek, V. Szabó, T. Szabolics, T. Szetefi, Z. Szökefalvi-Nagy, A. Tereshchenko, H. Thomsen, D. Timmermann, H. Tittes, K. Toi, M. Tournianski, U.v. Toussaint, J. Tretter, S. Tulipán, P. Turba, R. Uhlemann, J. Urban, E. Urbonavicius, P. Urlings, S. Valet, D. Van Eester, M. Van Schoor, M. Vervier, H. Viebke, R. Vilbrandt, M. Vrancken, T. Wauters, M. Weissgerber, E. Weiß, A. Weller, J. Wendorf, U. Wenzel, T. Windisch, E. Winkler, M. Winkler, J. Wolowski, J. Wolters, G. Wrochna, P. Xanthopoulos, H. Yamada, M. Yokoyama, D. Zacharias, J. Zajac, G. Zangl, M. Zarnstorff, H. Zeplien, S. Zoletnik, M. Zuin, Control Systems Technology, Science and Technology of Nuclear Fusion, Soft Matter and Biological Physics, Sensorics for fusion reactors, and Publica more...

Subjects
Nuclear and High Energy Physics, Steady state (electronics), LIMIT ANALYSIS, PLASMA, Nuclear engineering, MAGNET SYSTEM, Plasma, Fusion power, Condensed Matter Physics, W7-X, Electron cyclotron resonance, law.invention, PHYSICS, Data acquisition, Heating system, law, Wendelstein 7-X, Stellarator
Abstract

The next step in the Wendelstein stellarator line is the large superconducting device Wendelstein 7-X, currently under construction in Greifswald, Germany. Steady-state operation is an intrinsic feature of stellarators, and one key element of the Wendelstein 7-X mission is to demonstrate steady-state operation under plasma conditions relevant for a fusion power plant. Steady-state operation of a fusion device, on the one hand, requires the implementation of special technologies, giving rise to technical challenges during the design, fabrication and assembly of such a device. On the other hand, also the physics development of steady-state operation at high plasma performance poses a challenge and careful preparation. The electron cyclotron resonance heating system, diagnostics, experiment control and data acquisition are prepared for plasma operation lasting 30 min. This requires many new technological approaches for plasma heating and diagnostics as well as new concepts for experiment control and data acquisition. more...

Published
2013
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18. Combined operation of pellet injection and lower hybrid current drive in ASDEX

Author

W. Sandmann, M. Kornherr, V. Mertens, F. Leuterer, R. Lang, F. X. Söldner, R. Bartiromo, R. Loch, K. Ushigusa, and H.-S. Bosch

Subjects
Global energy, Materials science, Pellets, Deep penetration, Flux, Electron, Plasma, Condensed Matter Physics, Nuclear physics, Nuclear Energy and Engineering, Physics::Plasma Physics, Condensed Matter::Superconductivity, Physics::Space Physics, Pellet, Current (fluid), Atomic physics
Abstract

Simultaneous operation of lower hybrid current drive and pellet injection could be successfully achieved. With peripheral ablation of the pellets by suprathermal electrons, the same net inward flux of particles is found as with deep penetration of pellets into Ohmically heated plasmas. The density profile ne(r) peaks with the same increment of the peaking factor Qn=ne0/(ne) in both cases. The global energy confinement time rises with density, tau E approximately ne, in the combined operation. more...

Published
1991
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19. Observation of continuous divertor detachment in H-mode discharges in ASDEX upgrade

Author

K. Kiemer, K. Büchl, M. Albrecht, O. Gruber, Michael Kaufmann, W. Junker, G. Haas, W. Engelhardt, Neil A. Salmon, A. Carlson, V. Mertens, W. Treutterer, Martin Laux, D. P. Coster, M. Bessenrodt-Weberpals, M. Sokoll, J. Schweinzer, K. Asmussen, Marco Brambilla, K.H. Behringer, W. Herrmann, D. Meisel, Ana Elisa Bauer de Camargo Silva, F. Wesner, S. Deschka, C. S. Pitcher, H. Kollotzek, R. Wunderlich, Peter Lang, D. Fieg, H. B. Schilling, Harald Richter, M. Ulrich, Dirk Naujoks, P. Varela, Carmen García-Rosales, K.-H. Steuer, H. U. Fahrbach, J.-M. Noterdaeme, C. Dorn, Ch. Fuchs, A. Eberhagen, K. Krieger, K. Schonmann, H. Röhr, F. Ryter, K. Lackner, W. Sandmann, G. Neu, H. P. Zehrfeld, H. D. Murmann, M. Alexander, T. Richter, O. Vollmer, A. Kallenbach, G. Lieder, R. Drube, R. Dux, H.-S. Bosch, W. Poschenrieder, G. Fußmann, M. Schittenhelm, J. Gernhardt, A. Stäbler, S. De Pena Hempel, R. Lang, M. Maraschek, W. Suttrop, W. Köppendörfer, Harald Schneider, A. R. Field, D. Zasche, H. Vernickel, U. Wenzel, M. Troppmann, M. Ballico, H. Salzmann, R. Neu, M. Kornherr, H. Wedler, E. Speth, Gerhard Raupp, M. E. Manso, Ralf Schneider, Patrick J. McCarthy, R. Merkel, B. Napiontek, U. Schumacher, B. Kurzan, B. Jüttner, L. Cupido, U. Seidel, G. Schramm, P. Ignacz, Wolf-Dieter Schneider, K. Behler, O. Gehre, K. F. Mast, G. Pautasso, J. Neuhauser, S. Fiedler, H. M. Mayer, J. Roth, M. Weinlich, H.J. DeBlank, H. U. Feist, Albrecht Herrmann, J. Stober, S. Hirsch, T. Kass, H. Zohm, B. Streibl, and F. Serra more...

Subjects
Materials science, DIII-D, Divertor, Mode (statistics), General Physics and Astronomy, chemistry.chemical_element, Plasma, Radiation, Neon, Energy confinement, Deuterium, chemistry, ASDEX Upgrade, Atomic physics
Abstract

Feedback-controlled puffing of neon and deuterium has been applied to control the edge-localized-mode behavior and the target plate power deposition during high-power H -mode discharges in ASDEX Upgrade. A regime has been found in which more than 90% of the heating power is lost through radiation and divertor detachment occurs, without deterioration of the energy confinement. The plasma remains in the H mode, exhibiting small-amplitude, high-frequency ELM's, which do not penetrate to the target plates in the strike zone region. more...

Published
1995

20. Wendelstein 7-X—Status of the project and commissioning planning

Author

M. Gasparotto, D. A. Hartmann, Thomas Klinger, H.-S. Bosch, C. Baylard, L. Wegener, R. Vilbrandt, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Tokamak, Project commissioning, Computer science, Mechanical Engineering, 01 natural sciences, 010305 fluids & plasmas, law.invention, Nuclear Energy and Engineering, law, 0103 physical sciences, Systems engineering, General Materials Science, Wendelstein 7-X, 010306 general physics, Stellarator, Civil and Structural Engineering
Abstract

The stellarator device Wendelstein 7-X (W7-X) is now in the final stage of assembly. All the machine components have been built and in mid 2014 the commissioning activities should start. The first objective of W7-X is to prove the stellarator optimization principles, i.e., to reach at least the same confinement quality as a similar sized tokamak. The second objective is to demonstrate stable high-power steady-state operation. In the present paper, after a short description of the device, the ongoing activities to complete the construction will be summarized, focusing on the optimization of the layout of the torus hall and on the completion and assembly of the in-vessel components. The main lessons learned during the assembly will be presented as well as the application of the quality control, the handling of non-conformities and the design change procedures. The planning of the commissioning sequences to perform the integral tests of the major W7-X systems is discussed in order to prepare the W7-X device to start plasma operation. more...

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22. Specific features of eddy current analysis with ANSYS® for fast plasma current decay event in W7-X

Author

H.-S. Bosch, I. Pagani, L. Wegener, West Team, F. Lucca, V. Bykov, Jiawu Zhu, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Physics, 020209 energy, Mechanical Engineering, Time constant, 02 engineering and technology, Plasma, 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, Computational physics, law.invention, Nuclear Energy and Engineering, law, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Eddy current, General Materials Science, Skin effect, Excitation, Stellarator, Civil and Structural Engineering, Voltage, Vector potential
Abstract

During the second operation phase (OP1.2) of the most advanced stellarator Wendelstein 7-X (W7-X), some events of fast plasma current decay with a time constant of about 1 ms were observed (for both toroidal and diamagnetic plasma currents). The events were triggered by Electron Cyclotron Current Drive (ECCD) and were much faster than the assumptions considered during the design phase of W7-X components: 100 kA and 2.7 MA plasma current discharge with the time constants of 140 and 50 ms for toroidal and diamagnetic currents respectively. During the observed 1 ms discharge of maximum expected plasma currents, significant eddy currents are expected to be induced in some components with resulting electro-magnetic (EM) forces. In order to avoid unnecessary changes on as-built components, evaluation of the eddy currents / EM forces with high accuracy is required, if the conservative simplified estimation shows criticality. As a result, a sophisticated EM model with plasma currents, superconducting (sc) coils, plasma vessel (PV) and multiple ports is developed in ANSYS® using the new element type SOLID236 / 237 (edge-based formulation), which is much more accurate than the legacy elements SOLID97 (vector potential formulation). The specific features of using SOLID236 elements for eddy current analysis are studied and presented in this paper. This includes the application of boundary conditions on sector EM model, modelling of excitation currents, field and eddy current accuracy, skin effect, shielding effect, voltage in conducting components, etc. Most of the issues are studied in comparison with SOLID97 elements. Finally, the pros and cons of SOLID236 and SOLID97 elements are summarized, and the experiences during the W7-X EM analyses are presented. more...

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