Relativistic oblique shocks with ordered or random magnetic fields: tangential field governs

Abstract

Relativistic magnetohydrodynamic shocks are efficient particle accelerators, often invoked in the models of gamma-ray bursts (GRBs) and shock-powered fast radio bursts (FRBs). Most theoretical studies assume a perpendicular shock with an ordered magnetic field perpendicular to the shock normal. However, the degree of magnetization $\sigma$ and the magnetic field geometry in shock-powered GRB/FRB scenarios are still poorly constrained by observations. Analogous to the magnetization $\sigma$ associated with the total field strength, we define a tangential magnetization ${\sigma }_{\perp }$ associated with the tangential field component. We explore the jump conditions of magnetized relativistic shocks, either with an ordered field of arbitrary inclination angle or with a random field of arbitrary anisotropy. In either case, we find that the jump conditions of relativistic shocks are governed by the tangential magnetization ${\sigma }_{\perp }$ instead of the total magnetization $\sigma$, insensitive to the inclination angles or the anisotropy of the pre-shock magnetic field. The approximated analytical solution developed in this work could serve as a quick check for numerical simulations and apply to theoretical studies of GRBs/FRBs with a more general field geometry.

13 pages, 4 figures, accepted for publication in MNRAS

References in corpus (19)

• The Internal-Collision-Induced Magnetic Reconnection and Turbulence (ICMART) Model of Gamma-Ray Bursts
• Fast radio bursts as synchrotron maser emission from decelerating relativistic blast waves
• Relativistic Jets Shine through Shocks or Magnetic Reconnection?
• The Physical Mechanisms of Fast Radio Bursts
• A bimodal burst energy distribution of a repeating fast radio burst source
• Diverse polarization angle swings from a repeating fast radio burst source
• Ten per cent polarized optical emission from GRB 090102
• The synchrotron maser emission from relativistic shocks in Fast Radio Bursts: 1D PIC simulations of cold pair plasmas
• Deceleration of arbitrarily magnetized GRB ejecta: the complete evolution
• Phenomenology of Reverse-Shock Emission in the Optical Afterglows of Gamma Ray Bursts
• Coherent Electromagnetic Emission from Relativistic Magnetized Shocks
• On the existence of a reverse shock in magnetized GRB ejecta
• Constraining the magnetic field structure in collisionless relativistic shocks with a radio afterglow polarization upper limit in GW170817
• Magnetohydrodynamic Effects in Propagating Relativistic Jets: Reverse Shock and Magnetic Acceleration
• Internal shocks in relativistic outflows: collisions of magnetized shells
• Polarimetry and Photometry of Gamma-Ray Bursts with RINGO2
• Very Bright Prompt and Reverse Shock Emission of GRB 140512A
• Corrugation of relativistic magnetized shock waves
• A Mechanical Model for Magnetized Relativistic Blastwaves

Cited by in corpus (1)

• Synchrotron Polarization of Gamma-Ray Burst Afterglow Shocks with Hydrodynamic-scale Turbulent Magnetic Field