Electron-Ion Temperature Ratio in Astrophysical Shocks
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/T 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/T 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.
Cite
@article{arxiv.2303.08849,
title = {Electron-Ion Temperature Ratio in Astrophysical Shocks},
author = {John C. Raymond and Parviz Ghavamian and Artem Bohdan and Dongsu Ryu and Jacek Niemiec and Lorenzo Sironi and Aaron Tran and Elena Amato and Masahiro Hoshino and Martin Pohl and Takanobu Amano and Federico Fiuza},
journal= {arXiv preprint arXiv:2303.08849},
year = {2023}
}