On the stability of small-scale ballooning modes in mirror traps

TL;DR

This paper investigates how steep radial pressure profiles affect the stability of small-scale ballooning modes in mirror traps, revealing that increased steepness lowers the critical beta for instability, which in turn smooths the plasma profile.

Contribution

It demonstrates the relationship between pressure profile steepening and ballooning mode stability, providing new insights into plasma behavior in mirror traps.

Findings

Steepening of pressure profile decreases critical beta for instability.

Small-scale ballooning instability causes smoothing of the radial plasma profile.

Critical beta of 0.72 for a parabolic pressure profile in gas-dynamic traps.

Abstract

It is shown that steepening of the radial plasma pressure profile leads to a decrease in the critical value of beta, above which small-scale balloon-type perturbations in a mirror trap become unstable. This means that small-scale ballooning instability leads to a smoothing of the radial plasma profile. This fact seems to have received little attention in the available publications. The critical beta values for the real magnetic field of the gas-dynamic trap was also calculated. In the best configuration the critical beta 0.72 is obtained for a plasma with a parabolic radial pressure profile.