Kinetic Alfvén waves in plasmas with heavy ions

Abstract

Since its wide identification in measurements by satellites in space plasmas as well as its potential importance in the energization of plasma particles, the kinetic Alfvén wave (KAW) has been discussed extensively in the two-component (electron-proton) plasma model. The component of heavy ions, however, can frequently be found in space and astrophysical plasmas and can affect considerably the properties of the KAWs in them. In this paper, based on a three-component (i.e., electrons, protons, and heavy ions) plasma model, characteristics of KAWs are investigated. The results show that the dispersion of KAWs splits up into two branches. In the long wavelength limit, one branch has an asymptotic solution of shear Alfvén waves, while the other approaches an electrostatic wave with a frequency between the proton and heavy ion gyrofrequencies. Their polarization and resonance are also discussed.