Influence of electron-ion collisions on Buneman instability in fully ionized plasma

Abstract

The stability of a fully ionized plasma with a relative electron-ion (e-i) motion is considered taking into account the e-i collisions of high level. The relative e-i drift speed is assumed to be much higher than the thermal spread of electrons, and in the absence of collisions the system is subject to the low frequency and strongly growing Buneman instability. The transport equation with the Landau collision integral is solved taking into account the dependence of the collision frequency on the velocity of colliding particles. The effective frequency of e-i collisions is determined as a function of the system parameters. It is shown that with an increase in the level of e-i collisions the Buneman instability gradually transforms to the instability of dissipative type. This transition is traced in detail. The dependence of the growth rate on collision frequency upon this transformation is obtained.

The Behavior of Streaming Instabilities in Dissipative Plasma

“…In the absence of dissipation the velocities of unstable perturbations range from 0 to the group velocity v 0 . The length of the induced wave train increases as l ≈ v 0 t. The condition [1,16,17]. This once again justifies that high-level dissipation transforms the BI to DSI.…”

“…If ν << δ 0 , this equation leads to small corrections to the expressions (17) and 18for characteristic velocities and for the maximal growth rate in the peak. In the opposite case of highlevel dissipation, only the perturbations are unstable, whose velocity is close to the beam velocity u.…”