Solenoidal versus compressive turbulence forcing

TL;DR

This paper compares solenoidal and compressive turbulence forcing in high-resolution simulations, showing that compressive forcing leads to higher density fluctuations and star formation rates than solenoidal forcing.

Contribution

It provides a systematic analysis of how different turbulence driving mechanisms affect density statistics and star formation in supersonic turbulence models.

Findings

Compressive forcing results in three times larger density fluctuations.

Star formation rate is over ten times higher with compressive forcing.

Results align with observational data on turbulence and star formation.

Abstract

We analyze the statistics and star formation rate obtained in high-resolution numerical experiments of forced supersonic turbulence, and compare with observations. We concentrate on a systematic comparison of solenoidal (divergence-free) and compressive (curl-free) forcing, which are two limiting cases of turbulence driving. Our results show that for the same RMS Mach number, compressive forcing produces a three times larger standard deviation of the density probability distribution. When self-gravity is included in the models, the star formation rate is more than one order of magnitude higher for compressive forcing than for solenoidal forcing.