Absence of Electron Surfing Acceleration in a Two-Dimensional Simulation

TL;DR

This study uses two-dimensional PIC simulations to show that electron surfing acceleration, observed in one-dimensional models, does not occur in more realistic two-dimensional shock environments, impacting theories of electron acceleration in supernova remnants.

Contribution

It demonstrates that electron surfing acceleration is suppressed in two-dimensional simulations due to electrostatic potential structures, challenging previous one-dimensional findings.

Findings

Electron surfing acceleration is absent in 2D simulations.

Electrostatic potentials form structures that prevent electron trapping.

Implications for electron heating and acceleration in supernova remnants.

Abstract

Electron acceleration in high Mach number perpendicular shocks is investigated through two-dimensional electrostatic particle-in-cell (PIC) simulation. We simulate the shock foot region by modeling particles that consist of three components such as incident protons and electrons and reflected protons in the initial state which satisfies the Buneman instability condition. In contrast to previous one-dimensional simulations in which strong surfing acceleration is realized, we find that surfing acceleration does not occur in two-dimensional simulation. This is because excited electrostatic potentials have a two-dimensional structure that makes electron trapping impossible. Thus, the surfing acceleration does not work either in itself or as an injection mechanism for the diffusive shock acceleration. We briefly discuss implications of the present results on the electron heating and acceleration by shocks in supernova remnants.