Kinetic Alfvén waves in the temperature anisotropic space plasma with a kappa-Maxwellian distribution

Abstract

The dispersion and damping rate of kinetic Alfvén waves are studied in temperature anisotropic space plasma with kappa-Maxwellian distribution. Employing a kinetic approach, the wave frequency and damping rate of kinetic Alfvén waves and the modified ion acoustic waves are derived in a low β plasma, which both depend on the parameters κ and T⊥e/T∥e. The numerical analyses show that the wave frequency ωr/k∥VA of kinetic Alfvén waves is larger in kappa-Maxwellian plasma than that in Maxwellian case. The wave frequency of the modified ion acoustic waves in kappa-Maxwellian plasma is larger in the short-wave region but smaller in the long-wave region than that in Maxwellian case. Again, we found that the damping rate of kinetic Alfvén waves in kappa-Maxwellian plasma is stronger than that in Maxwellian case. The damping rate of modified ion acoustic waves in kappa-Maxwellian plasma is stronger in the short-wave region but weaker in the long-wave region than that in Maxwellian case. The impact of the parameter T⊥e/T∥eon the two modes is relatively small because we consider the low β case. These results are helpful for us to understand better the characteristics of kinetic Alfvén waves in space plasma.