Oscillatory instability of radiative shocks with multiple cooling processes |
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| Authors: | Curtis J Saxton Kinwah Wu Helen Pongracic & Giora Shaviv |
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| Institution: | Special Research Centre for Theoretical Astrophysics, School of Physics, University of Sydney, NSW 2006, Australia,;Sir Frank Packer Department of Theoretical Physics, School of Physics, University of Sydney, NSW 2006, Australia,;Air Operations Division, Aeronautical and Maritime Research Laboratory, Defence Science and Technology Organisation, VIC 3001, Australia,;Asher Space Research Institute and Department of Physics, Technion, Haifa 32000, Israel |
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| Abstract: | The stand-off shock formed in the accretion flow on to a stationary wall, such as the surface of a white dwarf, may be thermally unstable, depending on the cooling processes which dominate the post-shock flow. Some processes lead to instability, while others tend to stabilize the shock. We consider competition between the destabilizing influence of thermal bremsstrahlung cooling, and a stabilizing process which is a power law in density and temperature. Cyclotron cooling and processes which are of order 1, 3/2 and 2 in density are considered. The relative efficiency and power-law indices of the second mechanism are varied, and particular effects on the stability properties and frequencies of oscillation modes are examined. |
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| Keywords: | accretion accretion discs shock waves binaries: close white dwarfs |
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