Systematic Optimization of Tokamaks for Ideal Magnetohydrodynamic Stability

Abstract
High-β plasmas, stable to all ideal magnetohydrodynamic modes, have been found by joint optimization of plasma cross sections and current profile shapes. No wall stabilization is used for the external kink. Dee cross sections are considered with varying aspect ratios. The maximum stable β varies from 5% at aspect ratio 4 to 10% at aspect ratio 2.5, and the optimum elongation is 1.8. The low-n kink modes are the most limiting.