Two-Dimensional MHD Structures in Heat-Releasing Plasma

Abstract

Thermal instability has been the subject of intensive research for several decades. It is considered to be responsible for various spatio-temporal structures formation in the solar atmosphere, interstellar media, planetary nebulae and other media. Nevertheless, a convincing explanation of these structures appearance remains an open question. In this paper, we focus our attention on the isentropic type of thermal instabilities only, which causes MHD waves amplification in plasma. It is well-known that MHD waves are highly anisotropic and the patterns formed cannot be properly described using one-dimensional approach. Therefore, this work aims to study the features of 2D structures and compare them with one-dimensional ones. It is shown that both 1D and 2D initial Gaussian density perturbations lead to the formation of travelling autowave (self-sustaining) magnetoacoustic (MA) pulse sequence. Moreover, one-dimensional slice of the pulses corresponding to the fast MA waves coincides with the results of previous one-dimensional simulations. Furthermore, the investigation reveals that highly anisotropic wave patterns become more pronounced with the increase of magnetic field magnitude.