Collisional Effects on Instabilities in Weakly Ionized Counterstreaming Plasmas

Document Type : Research Paper

Authors

1 Department of Physics Education, Farhangian University, P.O. Box 14665-889, Tehran, Iran

2 Department of Physics, Salman Farsi University of Kazerun, Kazerun, Iran

10.22128/ijaa.2026.3335.1249

Abstract

The growth and damping of instabilities in weakly ionized counterstreaming plasmas were investigated by using of the dispersion relation for electrostatic longitudinal waves. Initially, in the collisionless regime, the frequency spectrum and damping rate were calculated, revealing that energy dissipation is primarily governed by mechanisms such as Landau damping. Subsequently, by including electron–neutral and ion–neutral collision terms, the plasma response and consequently, the growth/damping rates of instabilities were modified. Collisions emerged as effective dissipation mechanisms. A comparison between the collisional and collisionless regimes indicates that the ion–neutral collision term and Landau damping contribute most significantly to instability damping, while the thermal effects of ions play a relatively weaker role in the damping rate. Furthermore, it was determined that an increase in the electron collision frequency reduces the damping rate and enhances instability growth.

Keywords