Alfvenic modes in a bi-Maxwellian electron-ion plasma

Abstract

Employing linearized Vlasov–Maxwell system, we derive a generalized dielectric tensor for a magnetized nonrelativistic bi-Maxwellian electron-ion plasma. Assuming low frequency waves in a low β plasma, a new dispersion relation describing oblique propagation of the Alfvenic modes is determined, incorporating the temperature anisotropies of both the electrons and ions and their finite Larmor radii effects. From the resulting dispersion relation for kinetic Alfven waves, analytical expressions are determined for both the kinetic (vt∥i⪡ω/k∥⪡vt∥e and me/mi⪡β⪡1) and the inertial (ω/k∥⪢vt∥e,i and β⪡me/mi) regimes. We observe that in both cases, the Alfvenic modes stand modified due to the acoustic effect arising from the temperature anisotropy, which may enhance or reduce the Alfven speed depending on the strength and signature of the anisotropies. A number of special cases are also retrieved under appropriate conditions.