Hannover 2010 – scientific programme

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P: Fachverband Plasmaphysik

P 15: Invited Talks Mayer, Liang, Wolfrum, Schulz-von der Gathen

P 15.2: Invited Talk

Thursday, March 11, 2010, 11:30–12:00, B 305

Active control of tokamak instabilities by resonant magnetic perturbations — •Yunfeng Liang — Forschungszentrum Jülich GmbH, Association EURATOM-FZ Jülich, Institut für Energieforschung - Plasmaphysik, Trilateral Euregio Cluster, D-52425 Jülich, Germany

The standard tokamak H-mode, which is foreseen as the ITER baseline operating scenario, is characterised by a steep plasma pressure gradient and associated increased current density at the edge transport barrier which exceeds a threshold value to drive magnetohydrodynamic (MHD) instabilities referred to as Edge Localized Modes (ELMs). The so-called Type-I ELMs lead to a periodic expulsion of a considerable fraction of the stored energy content onto the plasma facing components. The associated transient heat loads might cause excess erosion and lead to a strong reduction of the plasma facing components lifetime. Active control of ELMs by resonant magnetic perturbation fields offers an attractive method for ITER. D-III D has shown that type-I ELMs are completely suppressed when n = 3 magnetic perturbations are applied. On JET, the type-I ELM frequency rises by a factor of about 4-5 when a low n (1, 2) field is applied. The frequency of the mitigated ELMs is proportional to the input heating power similarly to type-I ELMs, but the controlled ELMs have a higher frequency and are smaller in amplitude. In this paper, an overview of the influence on the plasma confinement and key physics issues related to ELM control with magnetic perturbation fields is given.