Measurement of the resistive-wall-mode stability in a rotating plasma using active MHD spectroscopy.
The stability of the resistive-wall mode (RWM) in DIII-D plasmas above the conventional pressure limit, where toroidal plasma rotation in the order of a few percent of the Alfve n velocity is sufficient to stabilize the n=1 RWM, has been probed using the technique of active MHD spectroscopy at frequencies of a few Hertz. The measured frequency spectrum of the plasma response to externally applied rotating resonant magnetic fields is well described by a single-mode approach and provides an absolute measurement of the damping rate and the natural mode rotation frequency of the stable RWM.
Reimerdes
H
H
Columbia University, New York, New York, USA.
Chu
M S
MS
Garofalo
A M
AM
Jackson
G L
GL
La Haye
R J
RJ
Navratil
G A
GA
Okabayashi
M
M
Scoville
J T
JT
Strait
E J
EJ