Publications in Scientific Journals:
M. Willensdorfer, S. Denk, E. Strumberger, W. Suttrop, B. Vanovac, D. Brida, M. Cavedon, I. Classen, M. Dunne, S. Fietz, R. Fischer, A. Kirk, F. Laggner, Y. Liu, T. Odstrcil, D. Ryan, E. Viezzer, H. Zohm, I. Luhmann, . ASDEX Upgrade Team, -. EUROfusion MST1 Team:
"Plasma response measurements of external magnetic perturbations using electron cyclotron emission and comparisons to 3D ideal MHD equilibrium";
Plasma Physics and Controlled Fusion,
The plasma response from an external n = 2 magnetic perturbation field in ASDEX Upgrade
has been measured using mainly electron cyclotron emission (ECE) diagnostics and a rigid
rotating field. To interpret ECE and ECE-imaging (ECE-I) measurements accurately, forward
modeling of the radiation transport has been combined with ray tracing. The measured data is
compared to synthetic ECE data generated from a 3D ideal magnetohydrodynamics (MHD)
equilibrium calculated by VMEC.
The measured amplitudes of the helical displacement around the outboard midplane are
in reasonable agreement with the one from the synthetic VMEC diagnostics. Both exceed the
predictions from the vacuum field calculations and indicate the presence of a kink response at
the edge, which amplifies the perturbation. VMEC and MARS-F have been used to calculate
the properties of this kink mode. The poloidal mode structure of the magnetic perturbation
of this kink mode at the edge peaks at poloidal mode numbers larger than the resonant
components |m|>|nq|, whereas the poloidal mode structure of its displacement is almost
resonant |m| |nq|. This is expected from ideal MHD in the proximity of rational surfaces.
The displacement measured by ECE-I confirms this resonant response.
magnetic perturbations, plasma response, ideal MHD, ECE, ECE imaging
Created from the Publication Database of the Vienna University of Technology.