# Kinetic simulations of nonrelativistic perpendicular shocks of young supernova remnants. I. Electron shock-surfing acceleration

## TL;DR

This study uses 2D PIC simulations to analyze electron shock-surfing acceleration at young supernova remnant shocks, revealing the importance of magnetic field orientation and simulation parameters for energization efficiency.

## Contribution

It demonstrates how magnetic field orientation affects electron acceleration in shock simulations and highlights the limitations of 2D models compared to 3D.

## Key findings

- Electron energization via Buneman waves is more efficient with out-of-plane magnetic fields.
- 2D simulations require parameter modifications to match 3D SSA efficiency.
- Electrons gain energy primarily from electrostatic fields of Buneman waves.

## Abstract

Electron injection at high Mach-number nonrelativistic perpendicular shocks is studied here for parameters that are applicable to young SNR shocks. Using high-resolution large-scale two-dimensional fully kinetic particle-in-cell (PIC) simulations and tracing individual particles we in detail analyze the shock surfing acceleration (SSA) of electrons at the leading edge of the shock foot. The central question is to what degree the process can be captured in 2D3V simulations. We find that the energy gain in SSA always arises from the electrostatic field of a Buneman wave. Electron energization is more efficient in the out-of-plane orientation of the large-scale magnetic field because both the phase speed and the amplitude of the waves are higher than for the in-plane scenario. Also, a larger number of electrons is trapped by the waves compared to the in-plane configuration. We conclude that significant modifications of the simulation parameters are needed to reach the same level of SSA efficiency as in simulations with out-of-plane magnetic field or 3D simulations.