Magnetized Kelvin-Helmholtz instability in the presence of a radiation field

TL;DR

This study investigates how a radiation field influences the Kelvin-Helmholtz instability, revealing that radiation generally destabilizes the system and enhances growth rates, which impacts energetic astrophysical phenomena.

Contribution

It provides a general linear analysis of radiation effects on KH instability, deriving a dispersion relation and demonstrating the destabilizing influence of radiation across various parameters.

Findings

Radiation field destabilizes KH modes over a wide parameter range.

Enhanced growth rates due to radiation can increase turbulence in astrophysical eruptions.

Radiation's role is significant in energetic phenomena like galaxy eruptions and supermassive star dynamics.

Abstract

The purpose of this study is to analyze the dynamical role of a radiation field on the growth rate of the unstable Kelvin - Helmholtz (KH) perturbations. As a first step toward this purpose, the analyze is done in a general way, irrespective of applying the model to a specific astronomical system. The transition zone between the two layers of the fluid is ignored. Then, we perform a linear analysis and by imposing suitable boundary conditions and considering a radiation field, we obtain appropriate dispersion relation. Unstable modes are studied by solving the dispersion equation numerically, and then growth rates of them are obtained. By analyzing our dispersion relation, we show that for a wide range of the input parameters, the radiation field has a destabilizing effect on KH instability. In eruptions of the galaxies or supermassive stars, the radiation field is dynamically important and because of the enhanced KH growth rates in the presence of the radiation; these eruptions can inject more momentum and energy into their environment and excite more turbulent motions.