Molecular clouds, colliding flows and HEDLA experiments: Star formation with the AstroBEAR AMR code

Abstract

In this contribution we present new simulations of colliding flows relevant to star formation studies which may also be relevant to future HEDLA experiments. We first discuss AstroBEAR a multi-physics MHD AMR code whose functionality and parallel performance make it a highly useful tool for star formation studies. We then present the results of two simulations of colliding flows that only differed with regards to the degree of inhomogeneity. One flow was completely uniform (Smooth), while the other contained many small over-densities in a lighter background (Clumpy) though with the same mean density, mass flux, & ram pressure. Despite these similarities, the two runs differed significantly with regards to their overall evolution, mixing, and core formation. The Smooth run formed cores early on throughout the cloud – while the inhomogeneities present in the Clumpy run drove a higher degree of small scale turbulence which seemed able to prevent local collapse. The Clumpy run did form cores but only after global collapse had ensued at around 20 Myr. The Smooth run managed to avoid global collapse for the duration of the simulation due to the increased splashing of material radially outwards as well as the higher pressure of the incoming material due to the details of the heating/cooling curve. In the final section we comment on possible applications of these studies to future HEDLA experiments. We conclude that key aspects of the flow evolution before gravitational collapse sets in may be amenable to laboratory studies.