Shock-triggered formation of magnetically-dominated clouds. II. Weak shock-cloud interaction in three dimensions

TL;DR

This study uses 3D magnetohydrodynamic simulations to explore how weak shocks interacting with magnetized atomic clouds can lead to the formation of magnetically dominated molecular clouds, emphasizing the importance of magnetic field orientation.

Contribution

It provides the first detailed 3D simulation analysis of weak shock interactions with magnetized clouds, highlighting the role of magnetic field orientation in cloud formation.

Findings

Small angles between shock normal and magnetic field produce observed-like clouds.

Magnetic field orientation significantly influences cloud morphology.

Weak shocks can trigger formation of magnetically dominated clouds.

Abstract

To understand the formation of a magnetically dominated molecular cloud from an atomic cloud, we study the interaction of a weak, radiative shock with a magnetised cloud. The thermally stable warm atomic cloud is initially in static equilibrium with the surrounding hot ionised gas. A shock propagating through the hot medium then interacts with the cloud. We follow the dynamical evolution of the shocked cloud with a time-dependent ideal magnetohydrodynamic code. By performing the simulations in 3D, we investigate the effect of different magnetic field orientations including parallel, perpendicular and oblique to the shock normal. We find that the angle between the shock normal and the magnetic field must be small to produce clouds with properties similar to observed molecular clouds.