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

Technical Report · Tue Jun 16 04:00:00 EDT 2009

DOI:https://doi.org/10.2172/958403· OSTI ID:958403

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.

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.

• Research Organization: Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC02-09CH11466
• OSTI ID: 958403
• Report Number(s): PPPL-4418
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
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)