BEXCO - Room B(103/104/105)
[CRI013] Electron injection and heating via turbulent magnetic reconnection at nonrelativistic shocks of young supernova remnants
- Artem BOHDAN
- Artem BOHDAN (Institute of Nuclear Physics, Kraków, Poland)
Electron injection constitutes a central unresolved problem for diffusive shock acceleration processes. Here we study perpendicular nonrelativistic collisionless shocks in a regime of high Mach numbers, as appropriate for young supernova remnants. We use high-resolution large-scale two-dimensional fully kinetic particle-in-cell simulations that sample a representative portion of the turbulent shock front and account for time-dependent effects of the cyclic shock reformation. The microphysics of perpendicular shocks in weakly magnetized plasmas is governed by ion reflection from the shock that leads to the formation of magnetic filaments in the shock ramp resulting from ion-beam filamentation instabilities, and also electrostatic Buneman modes in the shock foot. The latter can provide electron injection in the shock-surfing acceleration. Recent findings show that additional electron acceleration can also occur due to spontaneous magnetic reconnection triggered within magnetic filaments in the turbulent shock transition. We study conditions allowing for efficient electron pre-acceleration due to this process. We demonstrate a dependence of magnetic reconnection formation rate on inflowing plasma temperature and also on numerical parameters assumed in the simulations, such as the ion-to-electron mass ratio and the configuration of the average magnetic field with respect to the simulation plane. We discuss resulting injected electron spectra and relevance of our results to the physics of fully three-dimensional systems.