Pseudomoment fluid modeling: Electron Landau damping of ion-acoustic waves

This Brief Communication introduces a hierarchy of electron pseudomoment fluid equations to derive electron Landau damping of ion-acoustic waves. Exact agreement with kinetic predictions is obtained. The pseudomoment fluid formulation allows simple, analytic estimates of Landau damping for general, nonthermal electron distribution functions in Vlasov plasmas. Successful truncation of the pseudomoment hierarchy suggests a novel definition of electron temperature away from thermal equilibrium in the low-frequency regime