Time-dependent simulations of steady C-type shocks

TL;DR

This paper presents advanced time-dependent simulations of steady C-type shocks in dusty plasmas, incorporating detailed dust grain physics, ionization, and thermal processes, revealing the influence of dust on shock structure and magnetic field rotation.

Contribution

It introduces a novel, comprehensive model for oblique fast-mode shocks that combines dust dynamics with self-consistent microphysics, capable of modeling transient phenomena.

Findings

Dust grains significantly influence shock structure at high densities.

Magnetic field rotation occurs in the shock front, especially with small shock angles.

The method is robust and adaptable to non-equilibrium conditions.

Abstract

Using a time-dependent multifluid, magnetohydrodynamic code, we calculated the structure of steady perpendicular and oblique C-type shocks in dusty plasmas. We included relevant processes to describe mass transfer between the different fluids, radiative cooling by emission lines and grain charging and studied the effect of single-sized and multiple sized grains on the shock structure. Our models are the first of oblique fast-mode molecular shocks in which such a rigorous treatment of the dust grain dynamics has been combined with a self-consistent calculation of the thermal and ionisation structures including appropriate microphysics. At low densities the grains do not play any significant role in the shock dynamics. At high densities, the ionisation fraction is sufficiently low that dust grains are important charge and current carriers and, thus, determine the shock structure. We find that the magnetic field in the shock front has a significant rotation out of the initial upstream plane. This is most pronounced for single-sized grains and small angles of the shock normal with the magnetic field. Our results are similar to previous studies of steady C-type shocks showing that our method is efficient, rigorous and robust. Unlike the method employed in the previous most detailed treatment of dust in steady oblique fast-mode shocks, ours allows a reliable calculation even when chemical or other conditions deviate from local statistical equilibrium. We are also able to model transient phenomena.