MHD Shock-Clump Evolution with Self-Contained Magnetic Fields

Abstract

We study the interaction of strong shock waves with magnetized clumps. Previous numerical work focused on the simplified scenario in which shocked clumps are immersed in a globally uniform magnetic field that extends through both the clump and the ambient medium. Here we consider the complementary circumstance in which the field is completely self-contained within the clumps. This could arise naturally during clump formation via dynamical or thermal instabilities for example as magnetic field pinches off from the ambient medium. Using our AMR MHD code AstroBEAR, we carry out a series of simulations with magnetized clumps that have different self-contained magnetic field configurations. We find that the clump and magnetic evolution are sensitive to the fraction of magnetic field aligned with versus perpendicular to the shock normal. The relative strength of magnetic pressure and tension in the different field configurations allows us to analytically understand the different cases of post-shock evolution. We also show how turbulence and the mixing it implies depends of the initial field configuration and suggest ways in which observed shock-clump morphology may be used as a proxy for identifying internal field topologies a posteriori.

36 pages, 16 figures. ApJ, accepted

References in corpus (5)

• Simulating Magnetohydrodynamical Flow with Constrained Transport and Adaptive Mesh Refinement; Algorithms & Tests of the AstroBEAR Code
• The importance of magnetic-field-oriented thermal conduction in the interaction of SNR shocks with interstellar clouds
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• Magnetic field amplification in accretion discs around the first stars: implications for the primordial IMF
• On the dynamics and survival of fractal clouds in galactic winds
• The turbulent destruction of clouds - III. Three dimensional adiabatic shock-cloud simulations
• The Launching of Cold Clouds by Galaxy Outflows III: The Influence of Magnetic Fields
• Triggered Star Formation and Its Consequences
• A comparison of shock-cloud and wind-cloud interactions: The longer survival of clouds in winds
• The interaction of a magnetohydrodynamical shock with a filament
• The isothermal evolution of a shock-filament interaction