A second-order theory for the ion-acoustic heat flux instability

Abstract

A second-order theory for electrostatic instabilities driven by the free energy in the relative drifts of plasma components in an infinite homogeneous, Vlasov plasma is constructed. General expressions for the wave–particle exchange rates of momentum, energy and heat flux are derived. Under the boundary condition of constant current, new terms arise which significantly modify the conventional quasi-liner results. The theory is applied to the B = 0 ion-acoustic heat flux instability, and exchange rates are obtained which are suitable for inclusion in electron fluid models of thermal transport.