Investigation of Resistive Wall Mode Stabilization Physics in High-beta Plasmas Using Applied Non-axisymmetric Fields in NSTX

Sontag, A. C. ; Sabbagh, S. A. ; Zhu, W. ; Menard, J. E. ; Bell, R. E. ; Bialek, J. M. ; Bell, M. G. ; Gates, D. A. ; Glasser, A. H. ; LeBlanc, B. P. ; Shaing, K. C. ; Stutman, D. ; Tritz, K. L.

关键词: AMPLIFICATION;    ASPECT RATIO;    COMMISSIONING;    DAMPING;    EXTRAPOLATION;    HIGH-BETA PLASMA;    MAGNETIC FIELDS;    MODIFICATIONS;    PHYSICS;    PLASMA;    ROTATION;    STABILITY;    STABILIZATION Tokamak NSTX;    Spherical Tokamak;    Stability;    Ideal Hydromagnetic;    Stabilization;    Feedback;    Magnetohydrodynamics (MHD);   

DOI  :  10.2172/958403
RP-ID  :  PPPL-4418
PID  :  OSTI ID: 958403
Others  :  TRN: US0902864

学科分类：原子、分子光学和等离子物理

美国|英语

来源: SciTech Connect

【 摘 要 】

The National Spherical Torus Experiment (NSTX) offers an operational space characterized by high-beta (βt = 39%, βN > 7, βN/βno-wall N > 1.5) and low aspect ratio (A > 1.27) to leverage the plasma parameter dependences of RWM stabilization and plasma rotation damping physics giving greater confidence for extrapolation to ITER. Significant new capability for RWM research has been added to the device with the commissioning of a set of six nonaxisymmetric magnetic field coils, allowing generation of fields with dominant toroidal mode number, n, of 1–3. These coils have been used to study the dependence of resonant field amplification on applied field frequency and RWMstabilization physics by reducing the toroidal rotation profile belowits steady-state value through non-resonant magnetic braking. Modification of plasma rotation profiles shows that rotation outside q = 2.5 is not required for passive RWM stability and there is large variation in the RWM critical rotation at the q = 2 surface, both of which are consistent with distributed dissipation models.