Plasma heating and particle acceleration in collisionless shocks through astrophysical observations
arXiv:2301.01183 · doi:10.1088/1361-6587/acb082
Abstract
Supernova remnants (SNRs), the products of stellar explosions, are powerful astrophysical laboratories, which allow us to study the physics of collisionless shocks, thanks to their bright electromagnetic emission. Blast wave shocks generated by supernovae (SNe) provide us with an observational window to study extreme conditions, characterized by high Mach (and Alfvenic Mach) numbers, together with powerful nonthermal processes. In collisionless shocks, temperature equilibration between different species may not be reached at the shock front. In this framework, different particle species might be heated at different temperatures (depending on their mass) in the post-shock medium of SNRs. SNRs are also characterized by a broadband nonthermal emission stemming at the shock front as a result of nonthermal populations of leptons and hadrons. These particles, known as cosmic rays, are accelerated up to ultrarelativistic energies via diffusive shock acceleration. If SNRs lose a significant fraction of their ram energy to accelerate cosmic rays, the shock dynamics should be altered with respect to the adiabatic case. This shock modification should result in an increase of the total shock compression ratio with respect to the Rankine-Hugoniot value of 4. Here I show that the combination of X-ray high resolution spectroscopy (to measure ion temperatures) and moderate resolution spectroscopy (for a detailed diagnostic of the post-shock density) can be exploited to study both the heating mechanism and the particle acceleration in collisionless shocks. I report on new results in the temperatures measured for different ion species in the remnant of SN 1987A. I also discuss evidence of shock modification recently obtained in the remnant of SN 1006 a. D., where the shock compression ratio increases significantly as the angle between the shock velocity and the ambient magnetic field is reduced.
Author's preprint. Accepted for publication in Plasma Physics and Controlled Fusion after minor revisions
References in corpus (13)
- Detection of the Characteristic Pion-Decay Signature in Supernova Remnants
- Simultaneous Acceleration of Protons and Electrons at Nonrelativistic Quasiparallel Collisionless Shocks
- A Physical Relationship Between Electron-Proton Temperature Equilibration and Mach Number in Fast Collisionless Shocks
- Spatial Structure and Collisionless Electron Heating in Balmer-dominated Shocks
- Cosmological shock waves
- Matter Mixing in Aspherical Core-collapse Supernovae: Three-dimensional Simulations with Single Star and Binary Merger Progenitor Models for SN 1987A
- Collisionless shock heating of heavy ions in SN 1987A
- Deep XMM-Newton Observations Reveal the Origin of Recombining Plasma in the Supernova Remnant W44
- The supernova remnant SN 1006 as a Galactic particle accelerator
- Additional evidence for a pulsar wind nebula in the heart of SN 1987A from multi-epoch X-ray data and MHD modeling
- Spectral Evolution of the X-Ray Remnant of SN 1987A: A High-Resolution HETG Study
- A spatially resolved study of hard X-ray emission in Kepler's SNR: indications of different regimes of particle acceleration
- X-ray Line Diagnostics of Ion Temperature at Cosmic-Ray Accelerating Collisionless Shocks