The Responses of Magnetically Sub-Critical Cores to Shocks

TL;DR

This study uses advanced MHD simulations to explore how fast shocks interact with magnetically supported, self-gravitating cores, revealing shock focusing effects and the role of gravity in core evolution.

Contribution

It provides new insights into shock-core interactions in magnetized, self-gravitating environments using adaptive mesh refinement MHD simulations.

Findings

Shock focusing causes high-density regions along magnetic field lines.

Self-gravity influences the evolution but not the maximum density reached.

Density differences depend on shock orientation relative to magnetic fields.

Abstract

An ideal magnetohydrodynamics (MHD) code with adaptive mesh refinement (AMR) was used to investigate the interactions of fast-mode shocks with self-gravitating, isothermal cores with mass-to-flux ratios that are somewhat below the minimum value required for gravitational collapse. We find that shock focussing produces colliding flows along the field lines that generate very high densities, even for relatively weak shocks. Self-gravity plays only a minor role in determining the highest density that is reached, but it does play a role in the subsequent evolution. The densities at comparable times differ by a factor of a few for shocks initially propagating perpendicularly or obliquely to the magnetic field in the ambient medium.