Observation of the growth of a magnetic vortex in the transition layer of a mildly relativistic oblique plasma shock

TL;DR

This study uses 2D particle simulations to observe the formation and growth of a magnetic vortex in a plasma shock, revealing potential mechanisms for magnetic field generation in gamma-ray burst jets.

Contribution

It demonstrates the development of a magnetic vortex structure in a relativistic plasma shock, linking simulation results to astrophysical phenomena.

Findings

Magnetic vortex structure forms at the shock front.

Electrons and magnetic fields reach energy equipartition with ions.

The structure resembles a force-free spheromak, relevant to GRB jets.

Abstract

A 2D particle simulation models the collision of two electron-ion plasma clouds along a quasi-parallel magnetic field. The collision speed is 0.9c and the density ratio 10. A current sheet forms at the front of the dense cloud, in which the electrons and the magnetic field reach energy equipartition with the ions. A structure composed of a solenoidal and a toroidal magnetic field grows in this sheet. It resembles that in the cross-section of the torus of a force-free spheromak, which may provide the coherent magnetic fields in gamma-ray burst (GRB) jets needed for their prompt emissions.