Radiation Reaction effects on Coherent Emission in Relativistic Magnetized Shocks

TL;DR

This paper investigates how radiation reaction effects influence coherent emission in relativistic magnetized shocks, revealing enhanced radiation intensity, altered spectra, and implications for fast radio burst sources.

Contribution

It demonstrates that radiation reaction significantly modifies particle dynamics and radiation properties in shocks, providing new insights into FRB emission mechanisms.

Findings

Radiation reaction suppresses electron energies in shocks.

It amplifies coherent radiation intensity and efficiency.

The spectrum shows upshifted peak frequency and broader bandwidth.

Abstract

Relativistic magnetized shocks are natural sources of coherent radiation, representing a promising framework for fast radio bursts (FRBs). This study explores how the radiation reaction (RR) effect, triggered by high-energy photon emissions during shock radiation, significantly alters particle dynamics and coherent radiation properties. Using kinetic particle simulations, we demonstrate that RR severely suppresses electron energies from shock acceleration, resulting in multiple coherent gyration cycles at the shock front. It amplifies the intensity of coherent radiation and boosts energy efficiency by several fold, as compared to the single gyration cycle in standard model of Relativistic magnetized shocks. We further find that the coherent radiation spectrum from RR-mediated shocks characterized by upshift peak frequency, broaden bandwidth, and peak spectral morphology. The results support the magnetized shock as a viable source of FRBs, by providing explanation for the bimodal energy distribution observed in repeating FRB 20121102A and the statistically positive correlation of luminosity and bandwidth between repeating and one-off FRBs in the CHIME/FRB catalog.