Electromagnetic current instabilities

Abstract

Linear electromagnetic waves in an infinite, homogenous current‐carrying Vlasov plasma with ion β≈1 are considered. Three instabilities emerge: a long wavelength, ’’kink‐like’’ mode, and two instabilities with wavenumbers greater than the reciprocal ion Larmor radius, the ’’electromagnetic ion acoustic instability’’ and the ’’whistler current instability.’’ The linear properties of these instabilities are investigated in detail; they have substantially lower thresholds than the electrostatic ion‐acoustic instability, and are generally favored by increasing ion β. In the regime of linear growth, the whistler current instability can give rise to an anomalous resistivity, and preferentially heats the ions.