Thermal Trigger for Solar Flares II: Effect of the Guide Magnetic Field

TL;DR

This paper examines how a guide magnetic field influences thermal instability and stability in the preflare current layer, revealing that weak fields promote instability while strong fields stabilize the structure.

Contribution

It extends previous models by including a longitudinal magnetic field, showing its effects on thermal instability and stability in solar flare precursors.

Findings

Weak longitudinal fields do not alter the thermal instability period and promote instability.

Strong longitudinal fields stabilize the current layer against thermal instability.

Abstract

We investigate the effect of the thermal imbalance on the structural stability of the magnetohydrodynamic model of the preflare current layer (Ledentsov, Sol. Phys. 296, 74, 2021). The piecewise homogeneous model of the current layer is supplemented by a magnetic field longitudinal with respect to the direction of the current. It is shown that the presence of a weak longitudinal field does not change the previously calculated spatial period of the thermal instability in the most expected range of the parameters of the preflare current layer and, moreover, contributes to the formation of the instability. On the other hand, a strong longitudinal magnetic field contributes to the spatial stabilization of the current layer.