Coherent Electromagnetic Emission from Relativistic Magnetized Shocks

Abstract

Relativistic magnetized shocks are a natural source of coherent emission, offering a plausible radiative mechanism for Fast Radio Bursts (FRBs). We present first-principles 3D simulations that provide essential information for the FRB models based on shocks: the emission efficiency, spectrum, and polarization. The simulated shock propagates in an $e^{\pm }$ plasma with magnetization $\sigma >1$. The measured fraction of shock energy converted to coherent radiation is $\simeq 10^{-3}{\sigma }^{-1}$, and the energy-carrying wavenumber of the wave spectrum is $\simeq 4{\omega }_{\mathrm{c}}/c$, where ${\omega }_{\mathrm{c}}$ is the upstream gyrofrequency. The ratio of the O-mode and X-mode energy fluxes emitted by the shock is $\simeq 0.4{\sigma }^{-1}$. The dominance of the X-mode at $\sigma \gg 1$ is particularly strong, approaching 100% in the spectral band around $2{\omega }_{\mathrm{c}}$. We also provide a detailed description of the emission mechanism for both X- and O-modes.

6 pages, 5 figures, accepted to PRL

References in corpus (7)

• Fast Radio Bursts
• Fast radio bursts as synchrotron maser emission from decelerating relativistic blast waves
• Simulations of relativistic collisionless shocks: shock structure and particle acceleration
• The synchrotron maser emission from relativistic shocks in Fast Radio Bursts: 1D PIC simulations of cold pair plasmas
• Plasmoid ejection by Alfvén waves and the fast radio bursts from SGR 1935+2154
• The synchrotron maser emission from relativistic magnetized shocks: Dependence on the pre-shock temperature
• Magnetic reconnection at the termination shock in a striped pulsar wind

Cited by in corpus (7)

• Three-dimensional dynamics of strongly twisted magnetar magnetospheres: Kinking flux tubes and global eruptions
• Filamentation of Fast Radio Bursts in magnetar winds
• Prospects for ultra-high-energy particle acceleration at relativistic shocks
• Kinetic Simulations of the Filamentation Instability in Pair Plasmas
• Testing afterglow models of FRB 200428 with early post-burst observations of SGR 1935+2154
• Density jump as a function of magnetic field strength for parallel collisionless shocks with anisotropic upstream pressure
• Reverse shock forming condition for magnetized relativistic outflows: reconciling theories and simulations