Non-modal Simon-Hoh instability of a plasma with a shearing Hall current

TL;DR

This paper introduces a new nonmodal analytical approach to study the Simon-Hoh plasma instability under sheared current conditions, revealing significant growth overlooked by traditional modal analysis.

Contribution

It presents the first nonmodal analysis of the S-H instability in sheared plasma currents, highlighting growth mechanisms absent in normal mode analysis.

Findings

Strong nonmodal growth identified for S-H instability

Nonmodal effects dominate when shearing rate exceeds uniform current growth rate

Subcritical perturbations exhibit nonmodal growth suppressed in uniform current

Abstract

A new analytical nonmodal approach to investigate the plasma instabilities driven by the sheared current is presented and applied to the analysis of the linear evolution of the Simon-Hoh (S-H) instability of a plasma in the inhomogeneous electric field. We found analytically strong nonmodal growth for this instability which is missed completely in the normal modes analysis but dominates the normal mode growth when the shearing rate of the current velocity is above the growth rate of the S-H instability with uniform current. It includes also the nonmodal growth for the subcritical perturbations, which are suppressed in plasma with uniform Hall current.