The magnetic field of molecular clouds

TL;DR

This paper reviews the role of magnetic fields in molecular clouds, emphasizing that turbulence is super-Alfvénic and supported by recent simulations, which impacts star formation processes.

Contribution

It provides a review and argument that molecular cloud turbulence is super-Alfvénic, supported by recent large-scale simulations of supernova-driven turbulence.

Findings

Molecular cloud turbulence is super-Alfvénic.

Recent simulations support the super-Alfvénic nature of MC turbulence.

Supernova-driven turbulence influences magnetic field properties in MCs.

Abstract

The magnetic field of molecular clouds (MCs) plays an important role in the process of star formation: it determins the statistical properties of supersonic turbulence that controls the fragmentation of MCs, controls the angular momentum transport during the protostellar collapse, and affects the stability of circumstellar disks. In this work, we focus on the problem of the determination of the magnetic field strength. We review the idea that the MC turbulence is super-Alfv\'{e}nic, and we argue that MCs are bound to be born super-Alfv\'{e}nic. We show that this scenario is supported by results from a recent simulation of supernova-driven turbulence on a scale of 250 pc, where the turbulent cascade is resolved on a wide range of scales, including the interior of MCs.