Stratified Resistive Tearing Instability

TL;DR

This paper investigates how stable stratification influences resistive tearing instabilities in highly conductive fluids, revealing a non-monotonic relationship between stratification strength and the fastest growing mode, with implications for solar physics.

Contribution

It generalizes previous models by analyzing the effect of stratification on tearing instability across a broad parameter range, combining analytical and numerical methods.

Findings

The fastest growing mode's length scale varies non-monotonically with stratification.

Analytical predictions are confirmed through numerical solutions.

Potential relevance to the solar tachocline is discussed.

Abstract

Resistive tearing instabilities are common in fluids that are highly electrically conductive and carry strong currents. We determine the effect of stable stratification on the tearing instability under the Boussinesq approximation. Our results generalise previous work that considered only specific parameter regimes, and we show that the length scale of the fastest growing mode depends non-monotonically on the stratification strength. We confirm our analytical results by solving the linearised equations numerically, and we discuss whether the instability could operate in the solar tachocline.