Current driven kink instabilities in relativistic jets: dissipation properties

TL;DR

This paper investigates how current driven kink instabilities in highly magnetized relativistic jets lead to magnetic energy dissipation through current sheet formation, with implications for particle acceleration and radiation in astrophysical sources.

Contribution

It provides a detailed analysis of the dissipation process during kink instabilities, highlighting the stages and dependencies on jet parameters, which was not thoroughly characterized before.

Findings

Magnetic energy dissipation is independent of dissipation properties.

Dissipation occurs in two stages: a peak at instability saturation and a subsequent flat turbulence phase.

The properties of dissipation phases depend on the jet's magnetic configuration and external conditions.

Abstract

We analyze the evolution of current driven kink instabilities of a highly magnetized relativistic plasma column, focusing in particular on its dissipation properties. The instability evolution leads to the formation of thin current sheets where the magnetic energy is dissipated. We find that the total amount of dissipated magnetic energy is independent of the dissipation properties. Dissipation occurs in two stages: a peak when the instability saturates, which is characterized by the formation of a helicoidal current sheet at the boundary of the deformed plasma column, followed by a weaker almost flat phase, in which turbulence develops. The detailed properties of these two phases depend on the equilibrium configuration and other parameters, in particular on the steepness of the pitch radial profile, on the presence of an external axial magnetic field and on the amount of magnetization. These results are relevant for high energy astrophysical sources, since current sheets can be the sites of magnetic reconnection where particles can be accelerated to relativistic energies and give rise to the observed radiation.