Gravitating–radiative magnetohydrodynamic surface waves

Abstract

Radiative-magnetohydrodynamic (RMHD) equations along with a full set of Maxwell's equations are followed to formulate the charged surface waves at the interface of an incompressible, radiative, magnetized dusty plasma and vacuum, while assuming that the characteristic wave frequency is much smaller than the ion gyrofrequency, having an equilibrium background state. It is found that the separation of charges on the surface is followed by thermal motion, which further leads to a negative pressure gradient normal to the surface, hence the plasma–vacuum interface is under tension due to two different types of oppositely directed pressures. The dusty plasma RMHD set of equations admits a linear dispersion relation of surface Jeans instability of an incompressible dusty plasma, which exhibits a strong coupling between the electron surface charge and dust surface mass densities and we conclude that the surface densities of both electrons and dust as well as the dust inertia play major roles in the gravitational collapse of the surface of astrophysical objects such as stars, galaxies etc. Further, the growth rate of radiative surface waves is found to be function of both the temperature inhomogeneity, appearing due to thermal radiation heat flux, as well as the thermal radiation pressure. The present findings of charged surface waves may seek application at the astroscales.