A macroscopic interpretation for the problem of Landau damping of longitudinal oscillations in a collisionless plasma is investigated by including macroscopic fluid conservation of mass, momentum, and energy. It is shown that Landau damping may be derived macroscopically by appropriate consideration of the heat flux term for a collisionless plasma. This heat flux is expressed in terms of the perturbed velocity distribution function. A possible form of an equivalent complex thermal conductivity is postulated for a collisionless plasma. Both temporal and spacial damping are discussed.
Collisionless ion modeling in Hall thrusters: Analytical axial velocity distribution function and heat flux closures
