Compressible streaming instabilities in rotating thermal viscous objects

TL;DR

This paper investigates electromagnetic streaming instabilities in rotating, thermal, viscous astrophysical objects, revealing how collisional coupling and viscosity influence instability growth rates in various interstellar environments.

Contribution

It provides a detailed analysis of streaming instabilities considering viscosity, collisional effects, and different ionization levels in astrophysical plasmas, extending understanding of plasma behavior in space.

Findings

Growth rates depend on wave number spectrum.

Viscosity effects are negligible with strong neutral-ion coupling.

Instabilities occur where thermal pressure exceeds magnetic pressure.

Abstract

We study electromagnetic streaming instabilities in thermal viscous regions of rotating astrophysical objects, such as, protostellar and protoplanetary magnetized accretion disks, molecular clouds, their cores, and elephant trunks. The obtained results can also be applied to any regions of interstellar medium, where different equilibrium velocities between charged species can arise. We consider a weakly and highly ionized three-component plasma consisting of neutrals and magnetized electrons and ions. The vertical perturbations along the background magnetic field are investigated. The effect of perturbation of collisional frequencies due to density perturbations of species is taken into account. The growth rates of perturbations are found in a wide region of wave number spectrum for media, where the thermal pressure is larger than the magnetic pressure. It is shown that in cases of strong collisional coupling of neutrals with ions the contribution of the viscosity is negligible.