EFFECTS OF ELECTRON DRIFTS ON THE COLLISIONLESS DAMPING OF KINETIC ALFVEN WAVES IN THE SOLAR WIND

The collisionless dissipation of anisotropic Alfvenic turbulence is a promising candidate to solve the solar wind heating problem. Extensive studies examined the kinetic properties of Alfven waves in simple Maxwellian or bi-Maxwellian plasmas. However, the observed electron velocity distribution functions in the solar wind are more complex. In this study, we analyze the properties of kinetic Alfven waves (KAWs) in a plasma with two drifting electron populations. We numerically solve the linearized Maxwell-Vlasov equations and find that the damping rate and the proton- electron energy partition for KAWs are significantly modified in such plasmas, compared to plasmas without electron drifts. We suggest that electron drift is an important factor to take into account when considering the dissipation of Alfvenic turbulence in the solar wind or other beta similar to 1 astrophysical plasmas.