2ND-ORDER THEORY FOR THE ION-ACOUSTIC HEAT-FLUX INSTABILITY

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-linear 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. © 1979, Cambridge University Press. All rights reserved.