Particle-in-cell Simulations of Global Relativistic Jets with Helical Magnetic Fields

TL;DR

This study uses 3D relativistic particle-in-cell simulations to investigate how helical magnetic fields influence kinetic instabilities in global relativistic jets with different compositions, revealing suppression of some instabilities and emergence of new ones.

Contribution

It demonstrates the impact of helical magnetic fields on kinetic instabilities in relativistic jets, highlighting differences between electron-proton and electron-positron compositions.

Findings

Helical magnetic fields suppress certain kinetic instabilities.

Recollimation-like instability occurs in both jet types.

New types of instabilities can grow due to magnetic fields.

Abstract

We study the interaction of relativistic jets with their environment, using 3-dimensional relativistic particle-in-cell simulations for two cases of jet composition: (i) electron-proton ($e^{-}-p^{+}$) and (ii) electron-positron ($e^{\pm}$) plasmas containing helical magnetic fields. We have performed simulations of "global" jets containing helical magnetic fields in order to examine how helical magnetic fields affect kinetic instabilities such as the Weibel instability, the kinetic Kelvin-Helmholtz instability and the Mushroom instability. We have found that these kinetic instabilities are suppressed and new types of instabilities can grow. For the $e^{-}-p^{+}$ jet, a recollimation-like instability occurs and jet electrons are strongly perturbed, whereas for the $e^{\pm}$ jet, a recollimation-like instability occurs at early times followed by kinetic instability and the general structure is similar to a simulation without a helical magnetic field. We plan to perform further simulations using much larger systems to confirm these new findings.