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arXiv · 1509.06538

Bow shock fragmentation driven by a thermal instability in laboratory-astrophysics experiments

F. Suzuki-Vidal·S. V. Lebedev·A. Ciardi·L. A. Pickworth·R. Rodriguez·J. M. Gil·G. Espinosa·P. Hartigan·G. F. Swadling·J. Skidmore·G. N. Hall·M. Bennett·S. N. Bland·G. Burdiak·P. de Grouchy·J. Music·L. Suttle·E. Hansen·A. Frank
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Abstract

The role of radiative cooling during the evolution of a bow shock was studied in laboratory-astrophysics experiments that are scalable to bow shocks present in jets from young stellar objects. The laboratory bow shock is formed during the collision of two counter-streaming, supersonic plasma jets produced by an opposing pair of radial foil Z-pinches driven by the current pulse from the MAGPIE pulsed-power generator. The jets have different flow velocities in the laboratory frame and the experiments are driven over many times the characteristic cooling time-scale. The initially smooth bow shock rapidly develops small-scale non-uniformities over temporal and spatial scales that are consistent with a thermal instability triggered by strong radiative cooling in the shock. The growth of these perturbations eventually results in a global fragmentation of the bow shock front. The formation of a thermal instability is supported by analysis of the plasma cooling function calculated for the experimental conditions with the radiative packages ABAKO/RAPCAL.

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F. Suzuki-Vidal, S. V. Lebedev, A. Ciardi, L. A. Pickworth, R. Rodriguez, J. M. Gil, G. Espinosa, P. Hartigan, G. F. Swadling, J. Skidmore, G. N. Hall, M. Bennett, S. N. Bland, G. Burdiak, P. de Grouchy, J. Music, L. Suttle, E. Hansen, A. Frank. 2015-09-22. Bow shock fragmentation driven by a thermal instability in laboratory-astrophysics experiments. https://doi.org/10.1088/0004-637x%2F815%2F2%2F96

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