Fast-ion redistribution and loss due to edge perturbations in the ASDEX Upgrade, DIII-D and KSTAR tokamaks

TitleFast-ion redistribution and loss due to edge perturbations in the ASDEX Upgrade, DIII-D and KSTAR tokamaks
Publication TypeJournal Article
Year of Publication2013
AuthorsM. García-Muñoz, S. Akaslompolo, O. Asunta, J. Boom, X. Chen, I.G.J. Classen, R. Dux, T.E Evans, S. Fietz, R.K Fisher, C. Fuchs, B. Geiger, M. Hoelzl, V. Igochine, Y.M Jeon, J. Kim, J.Y Kim, B. Kurzan, N. Lazanyi, T. Lunt, R.M McDermott, M. Nocente, D.C Pace, T.L Rhodes, M. Rodriguez-Ramos, K. Shinohara, W. Suttrop, M.A VanZeeland, E. Viezzer, M. Willensdorfer, E. Wolfrum, theASDEX Upgrade, DIII-D Team, KSTAR Teams
JournalNuclear Fusion

The impact of edge localized modes (ELMs) and externally applied resonant and non-resonant magnetic perturbations (MPs) on fast-ion confinement/transport have been investigated in the ASDEX Upgrade (AUG), DIII-D and KSTAR tokamaks. Two phases with respect to the ELM cycle can be clearly distinguished in ELM-induced fast-ion losses. Inter-ELM losses are characterized by a coherent modulation of the plasma density around the separatrix while intra-ELM losses appear as well-defined bursts. In high collisionality plasmas with mitigated ELMs, externally applied MPs have little effect on kinetic profiles, including fast-ions, while a strong impact on kinetic profiles is observed in low-collisionality, low q 95 plasmas with resonant and non-resonant MPs. In low-collisionality H-mode plasmas, the large fast-ion filaments observed during ELMs are replaced by a loss of fast-ions with a broad-band frequency and an amplitude of up to an order of magnitude higher than the neutral beam injection prompt loss signal without MPs. A clear synergy in the overall fast-ion transport is observed between MPs and neoclassical tearing modes. Measured fast-ion losses are typically on banana orbits that explore the entire pedestal/scrape-off layer. The fast-ion response to externally applied MPs presented here may be of general interest for the community to better understand the MP field penetration and overall plasma response.







Alternate TitleNucl. Fusion

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