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arXiv · 1605.09591

Stability Analysis of Convection in the Intracluster Medium

Himanshu Gupta·Shailendra K. Rathor·Martin E. Pessah·Sagar Chakraborty
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Abstract

We use the machinery usually employed for studying the onset of Rayleigh--Bénard convection in hydro- and magnetohydro-dynamic settings to address the onset of convection induced by the magnetothermal instability and the heat-flux-buoyancy-driven-instability in the weakly-collisional magnetized plasma permeating the intracluster medium. Since most of the related numerical simulations consider the plasma being bounded between two `plates' on which boundary conditions are specified, our strategy provides a framework that could enable a more direct connection between analytical and numerical studies. We derive the conditions for the onset of these instabilities considering the effects of induced magnetic tension resulting from a finite plasma beta. We provide expressions for the Rayleigh number in terms of the wave vector associated with a given mode, which allow us to characterize the modes that are first to become unstable. For both the heat-flux-buoyancy-driven-instability and the magnetothermal instability, oscillatory marginal stable states are possible.

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Himanshu Gupta, Shailendra K. Rathor, Martin E. Pessah, Sagar Chakraborty. 2016-05-31. Stability Analysis of Convection in the Intracluster Medium. https://doi.org/10.1016/j.physleta.2016.05.026

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