Session KP01 - Poster Session III.
POSTER session, Tuesday afternoon, March 23
Exhibit Hall, GWCC
In high temperature tokamaks, nonideal MHD instabilities limit the achievable plasma pressure through the production of long wavelength nonlinearly evolving magnetic islands driven by neoclassical bootstrap current effects. However, in low aspect ratio tokamaks, the neoclassical effect competes with the stabilizing effects of pressure and good average curvature [S. E. Kruger, et al, Phys. Plasmas 5, 455 (1998)]. Prior analytic calculations of pressure/curvature effects on the nonlinear resistive growth of magnetic islands implemented a small aspect ratio, small beta expansion which is not appropriate for tight aspect ratio applications. In this work, we revisit this analytic calculation by relaxing the small aspect ratio, small beta constraints by considering an asymptotic expansion based solely on a small island width assumption. Implications for beta limits in tight aspect ratio tokamak configurations will be addressed.