Improved magnetohydrodynamic stability through optimization of higher order moments in cross-section shape of tokamaks

摘要

Optimization of the higher order moments-specifically the squareness-of a tokamak cross-section can significantly enhance the stability to ideal magnetohydrodynamic ballooning and kink modes. At conventional aspect ratios, it is shown that access to the second regime of ballooning stability is facilitated by moderate squareness. In a low aspect ratio, fully bootstrap current driven spherical torus, optimization of the squareness results in an increase in bof the order of 10%, leading to a configuration stable to ballooning, axisymmetric, and ideal n less than or equal to 5 kink modes at beta similar or equal to 67%. (C) 1999 American Institute of Physics. [S1070-664X(99)01804-2]. [References: 18]