Electron Kinetic Entropy across Quasi-Perpendicular Shocks |
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Authors: | Martin Lindberg Andris Vaivads Savvas Raptis Per-Arne Lindqvist Barbara L Giles Daniel Jonathan Gershman |
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Institution: | 1.Space and Plasma Physics, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, 114 28 Stockholm, Sweden; (A.V.); (S.R.); (P.-A.L.);2.NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA; (B.L.G.); (D.J.G.) |
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Abstract: | We use Magnetospheric Multiscale (MMS) data to study electron kinetic entropy per particle across Earth’s quasi-perpendicular bow shock. We have selected 22 shock crossings covering a wide range of shock conditions. Measured distribution functions are calibrated and corrected for spacecraft potential, secondary electron contamination, lack of measurements at the lowest energies and electron density measurements based on plasma frequency measurements. All crossings display an increase in electron kinetic entropy across the shock being positive or zero within their error margin. There is a strong dependence of on the change in electron temperature, , and the upstream electron plasma beta, . Shocks with large have large . Shocks with smaller are associated with larger . We use the values of , and density change to determine the effective adiabatic index of electrons for each shock crossing. The average effective adiabatic index is . |
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Keywords: | space plasma electron kinetic entropy quasi-perpendicular shock adiabatic index |
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