Stabilization of the $m=1$ mode in a long-thin mirror trap with high-beta anisotropic plasmas

Abstract

Stability of a "rigid" ballooning mode m = 1 is studied for a mirror axisymmetric trap designed to hold anisotropic plasma with a large beta (β, the ratio of plasma pressure to magnetic field pressure). It was found that for effective wall stabilization, the beta parameter must exceed some critical value βcrit. The dependence of βcrit on the plasma anisotropy, mirror ratio and width of vacuum gap between plasma and lateral wall was studied. Unlike the works of other authors focused on the plasma model with a sharp boundary, we calculated the boundaries of the stability zone for a number of diffuse radial pressure profiles and several axial magnetic field profiles.With a combination of a conducting side wall and conducting ends imitating the attachment of end MHD stabilizers to the central cell of an open trap, there are two critical values of beta and two stability zones, β < βcrit1 and β > βcrit2, which can merge, making the entire range of allowable beta values 0 < β < 1 stable.