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arXiv · 2303.08849

Electron-Ion Temperature Ratio in Astrophysical Shocks

John C. Raymond·Parviz Ghavamian·Artem Bohdan·Dongsu Ryu·Jacek Niemiec·Lorenzo Sironi·Aaron Tran·Elena Amato·Masahiro Hoshino·Martin Pohl·Takanobu Amano·Federico Fiuza
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Abstract

Collisionless shock waves in supernova remnants and the solar wind heat electrons less effectively than they heat ions, as is predicted by kinetic simulations. However, the values of T$_e$/T$_p$ inferred from the H alpha profiles of supernova remnant shocks behave differently as a function of Mach number or Alfv\'{e}n Mach number than what is measured in the solar wind or predicted by simulations. Here we determine T$_e$/T$_p$ for supernova remnant shocks using H alpha profiles, shock speeds from proper motions, and electron temperatures from X-ray spectra. We also improve the estimates of sound speed and Alfv\'{e}n speed used to determine Mach numbers. We find that the H alpha determinations are robust and that the discrepancies among supernova remnant shocks, solar wind shocks and computer-simulated shocks remain. We discuss some possible contributing factors, including shock precursors, turbulence and varying preshock conditions.

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John C. Raymond, Parviz Ghavamian, Artem Bohdan, Dongsu Ryu, Jacek Niemiec, Lorenzo Sironi, Aaron Tran, Elena Amato, Masahiro Hoshino, Martin Pohl, Takanobu Amano, Federico Fiuza. 2023-03-15. Electron-Ion Temperature Ratio in Astrophysical Shocks. https://doi.org/10.3847/1538-4357%2Facc528

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