Dust-acoustic waves and stability in the permeating dusty plasma: I. Maxwellian distribution

TL;DR

This paper investigates the stability of dust-acoustic waves in permeating dusty plasmas with Maxwellian distributions, deriving wave frequency and growth rates, and analyzing how flow velocity influences wave stability.

Contribution

It provides a theoretical analysis of dust-acoustic wave stability in permeating dusty plasmas considering Maxwellian velocity distributions, including limiting cases and numerical examples.

Findings

Waves are generally unstable when the flow velocity is much larger than the phase velocity.

Waves become unstable at small wave numbers when the flow velocity is large.

Wave stability depends strongly on the flow velocity and physical conditions of the plasma.

Abstract

The dust-acoustic waves and their stability in the permeating dusty plasma with the Maxwellian velocity distribution are investigated. We derive the dust-acoustic wave frequency and instability growth rate in two limiting physical cases that the thermal velocity of the flowing dusty plasma is (a) much larger than, and (b) much smaller than the phase velocity of the waves. We find that the stability of the waves depend strongly on the velocity of the flowing dusty plasma in the permeating dusty plasma. The numerical analyses are made based on the example that a cometary plasma tail is passing through the interplanetary space plasma. We show that, in case (a), the waves are generally unstable for any flowing velocity, but in case (b), the waves become unstable only when the wave number is small and the flowing velocity is large. When the physical conditions are between these two limiting cases, we gain a strong insight into the dependence of the stability criterions on the physical conditions in the permeating dusty plasma.