Effects of collisional and viscous dissipations on the ion-acoustic–Langmuir interactions

Abstract

A pair of modified Zakharov equations coupling the high-frequency Langmuir oscillations to the low-frequency ion-acoustic perturbations in a turbulent, collisional plasma with a neutral background is derived. The time evolution of the coupled ion-acoustic–Langmuir solitons show that the electron–ion and electron–neutral collisions damp the Langmuir oscillations and let the ion density perturbations radiate away. On the other hand, the ion–neutral collisions damp the ion density perturbations letting the Langmuir oscillations flow out. In the case of ion viscosity, however, both the ion density perturbations and the Langmuir oscillations radiate away one after the other. In these processes, electron–ion and electron–neutral collisions seem to dominate over the other two.