ION-ACOUSTIC-WAVES IN PLASMAS WITH COLLISIONAL ELECTRONS

We have developed an analytical theory of ion acoustic wave (IAW) damping and electron heat conductivity in plasmas with an arbitrary electron collisionality. We have found that deviations from the collisionless electron Landau damping occur for the wave numbers keiZ2/3, where ei is the electron mean free path for collisions with ions. In the regime of intermediate collisionality the IAW damping is proportional to k4/7 and the nonlocal electron heat conductivity is proportional to k-4/7. The transition into the hydrodynamic regime occurs for kei0.1Z1/2. © 1994 The American Physical Society.