München 2019 – scientific programme
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P: Fachverband Plasmaphysik
P 7: Helmholtz Graduate School II - Magnetic Confinement I
P 7.1: Invited Talk
Monday, March 18, 2019, 16:30–17:00, HS 21
3-D physics of the tokamak edge — •Matthias Willensdorfer1, Tyler Cote2, Michael Griener1, David Ryan3, Erika Strumberger1, Wolfgang Suttrop1, Nengchao Wang4, Dominik Brida1, Marco Cavedon1, Severin Denk1, Mike Dunne1, Rainer Fischer1, Christopher Ham3, Chris Hegna2, Matthias Hoelzl1, Andrew Kirk3, Nils Leuthold1, Marc Maraschek1, Hartmut Zohm1, and The ASDEX Upgrade Team1 — 1Max Planck Institute for Plasma Physics, 85748 Garching, Germany — 2University of Wisconsin-Madison, Madison, Wisconsin 53706, USA — 3CCFE, Culham Science Centre, Abingdon, Oxon, OX14 3DB, UK — 4AEET, SEEE, HUST, Wuhan 430074, P R China
Non-axisymmetric perturbation coils in tokamaks are commonly used to modify the properties of the plasma edge. This can be beneficial for future fusion, since it allows to influence possible harmful edge instabilities.
Recent research has shown that the perturbation field from these coils excite static ideal magnetohydrodynamic (MHD) modes at the edge, which significantly distort the axisymmetry of tokamaks. This three-dimensional (3D) tokamak geometry is well described by MHD equilibrium codes originally developed for stellarators. Moreover, measurements of small (helically) localised instabilities combined with stability analysis demonstrate that the induced 3D geometry produces regions of lower stability on the plasma surface.