Magnetic Field Generation and Particle Energization at Relativistic Shear Boundaries in Collisionless Electron-Positron Plasmas

TL;DR

This study uses advanced simulations to explore how magnetic fields are generated and particles are energized at relativistic shear boundaries in collisionless electron-positron plasmas, revealing mechanisms relevant to astrophysical jets.

Contribution

It demonstrates efficient magnetic field generation and nonthermal particle acceleration at shear boundaries, providing new insights into relativistic plasma physics.

Findings

Magnetic fields are generated via streaming instabilities at the shear boundary.

Particles are accelerated to form a power-law energy distribution.

Results have implications for jet dissipation and radiation in astrophysics.

Abstract

Using 2.5-dimensional Particle-in-Cell simulations, we study the kinetic physics of relativistic shear flow boundary in collisionless electron-positron (e+e-) plasmas. We find efficient magnetic field generation and particle energization at the shear boundary, driven by streaming instabilities across the shear interface and sustained by the shear flow. Nonthermal, anisotropic high-energy particles are accelerated across field lines to produce a power-law tail, truncated at energies below the shear Lorentz factor. These results have important implications for the dissipation and radiation of jets in blazars, gamma-ray bursts and other relativistic outflows.