Two-Dimensional MHD Structures in Heat-Releasing Plasma
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.
This work was partially supported by the Ministry of Education and Science of Russian Federation under Competitiveness Enhancement Program of SSAU for 2013–2020 years and by State assignment to educational and research institutions under projects 3.1158.2017, by RFBR under grant 16-41-630591 r_a, 17-42-630224 r_a.
- 2.K.V. Krasnobaev, N.E. Sysoev, V. Yu, Tarev Nuclear Physics, Cosmic Rays, Astronomy (Moscow State University Press, Moscow, 1993), pp. 222–230Google Scholar
- 7.Y.B. Zel’dovich, Y.P. Raizer, Physics of Shock Waves and High-Temperature Hydrodynamic Phenomena, vol 1 (Academic, New York, 1966)Google Scholar