Open AccessInternal Kink Mode Dynamics in High-{beta} NSTX Plasmas
Author(s) -
J E Menard,
R E Bell,
E. D. Fredrickson,
D A Gates,
S M Kaye,
B P LeBlanc,
S S Medley,
W Park,
S A Sabbagh,
A Sontag,
D Stutman,
K Tritz,
W Zhu
Publication year - 2004
Language(s) - English
Resource type - Reports
DOI - 10.2172/836571
Subject(s) - toroid , plasma , flattening , physics , beta (programming language) , diamagnetism , atomic physics , tokamak , kink instability , stellarator , kinetic energy , angular momentum , ballooning , saturation (graph theory) , large helical device , torus , magnetic field , nuclear physics , classical mechanics , computer science , programming language , mathematics , geometry , quantum mechanics , astronomy , combinatorics
Saturated internal kink modes have been observed in many of the highest toroidal beta discharges of the National Spherical Torus Experiment (NSTX). These modes often cause rotation flattening in the plasma core, can degrade energy confinement, and in some cases contribute to the complete loss of plasma angular momentum and stored energy. Characteristics of the modes are measured using soft X-ray, kinetic profile, and magnetic diagnostics. Toroidal flows approaching Alfvenic speeds, island pressure peaking, and enhanced viscous and diamagnetic effects associated with high-beta may contribute to mode nonlinear stabilization. These saturation mechanisms are investigated for NSTX parameters and compared to experimental data