Electromagnetic instability in nonuniform resistive electron magnetohydrodynamics

Abstract

A local dispersion relation for electromagnetic modes in a nonuniform collisional magnetized electron plasma with fixed ion background is derived, taking into account equilibrium magnetic field and pressure gradients, as well as impurity radiation losses. The dispersion relation is then analyzed both analytically as well as numerically. It is found that for a low-β plasma, the principal source for the generation of unstable modes is the impurity radiation loss; whereas for a high-β plasma, the various effects such as the electron streaming, the electron–ion collisions, finite electron thermal conductivity, and impurity radiation losses are shown to be responsible for unstable perturbations. The results should be useful in the interpretation of nonthermal electromagnetic fluctuations in nonuniform collision-dominated magnetoplasmas with impurities.