Spontaneous generation of magnetic fields in thin layers of stratified plasma

Abstract

In this work, the processes of spontaneous generation of magnetic fields by Rayleigh–Benard convection in a thin layer of plasma in a constant gravitational field are investigated. The values of the critical Rayleigh number for stationary convection are obtained, and the criteria for the occurrence of instability leading to the generation of magnetic fields are determined within the framework of electron magnetic hydrodynamics (EMHD). The weakly nonlinear regime of magnetic fields generation is studied using the method of perturbation theory with respect to the small supercriticality parameter ε=(Ra−Rac)/Rac of the stationary Rayleigh number Rac. A nonlinear equation of the Ginzburg–Landau type is obtained, which describes the evolution of the stationary level of excited magnetic fields.