Dynamical Energy Dissipation of Relativistic Magnetic Bullets

TL;DR

This study uses relativistic magneto-hydrodynamic simulations to analyze how magnetic energy dissipates through shocks in highly magnetized relativistic outflows, relevant for gamma-ray bursts and blazars.

Contribution

It provides detailed numerical analysis of magnetic energy dissipation mechanisms and timescales in relativistic outflows, including single and multiple shock interactions.

Findings

Approximately 10% of magnetic energy converts to thermal energy via shocks.

Energy dissipation timescales vary with magnetization levels.

Results are relevant for understanding non-thermal emissions in astrophysical jets.

Abstract

To demonstrate the magnetic energy dissipation via relativistic shocks, we carry out spherically symmetrical one-dimensional special relativistic magneto-hydrodynamic simulations of highly magnetised outflows with an adaptive mesh refinement method. We first investigate the detail of the dynamical energy dissipation via interaction between a single ejecta and an external medium. The energy dissipation timescales, which affect the early behaviour of the afterglow emission in gamma-ray bursts, are estimated for a wide range of magnetisation. In addition, we demonstrate the internal shock dissipation in multiple interactions between magnetically dominated relativistic ejecta and kinetically dominated non-relativistic winds. Our numerical results show that almost 10% of the magnetic energy in the ejecta can be converted into the thermal energy of the relativistic and low-magnetised outflows via shocks in the rarefaction waves or the winds. Such hot and less magnetised outflows are relevant for observed non-thermal emissions in blazars or gamma-ray bursts.