Ion-Acoustic Wave Generation by Two Kinetic Alfvén Waves and Particle Heating

In this paper we have investigated the beat wave excitation of an ion-acoustic wave at the difference frequency of two kinetic (or shear) Alfvén waves propagating in a magnetized plasma with β<1 (β=8π n _e0 T _e/B ₀ ² , where n _e0 is the unperturbed electron number density, T _e is the electron temperature, and B ₀ is the external magnetic field). On account of the interaction between two kinetic Alfvén waves of frequencies ω ₁ and ω ₂, the ponderomotive force at the difference frequency ω ₁−ω ₂ leads to the generation of an ion-acoustic wave. Also because of the filamentation of the Alfvén waves, magnetic-field-aligned density dips are observed. In this paper we propose that the ion-acoustic wave generated by this mechanism may be one of the possible mechanisms for the heating and acceleration of solar wind particles.