Three-Dimensional Relativistic Magnetohydrodynamic Simulations of Current-Driven Instability. III. Rotating Relativistic Jets

TL;DR

This paper uses 3D relativistic MHD simulations to study how jet rotation and magnetic field distribution influence the development of current-driven kink instabilities in relativistic jets, revealing conditions for instability growth and saturation.

Contribution

It provides new insights into the nonlinear evolution of current-driven kink instabilities considering jet rotation and magnetic field profiles in relativistic jets.

Findings

Instability growth depends on the poloidal magnetic field distribution.

Strong growth occurs when the poloidal field decreases outward significantly.

Shallow poloidal profiles lead to slow development and eventual saturation.

Abstract

We have investigated the influence of jet rotation and differential motion on the linear and nonlinear development of the current-driven (CD) kink instability of force-free helical magnetic equilibria via three-dimensional relativistic magnetohydrodynamic simulations. In this study, we follow the temporal development within a periodic computational box. Displacement of the initial helical magnetic field leads to the growth of the CD kink instability. We find that, in accord with linear stability theory, the development of the instability depends on the lateral distribution of the poloidal magnetic field. If the poloidal field significantly decreases outwards from the axis, the initial small perturbations grow strongly, and if multiple wavelengths are excited non-linear interaction eventually disrupts the initial cylindrical configuration. When the profile of the poloidal field is shallow, the instability develops slowly and eventually saturates. We briefly discuss implications of our findings for Poynting dominated jets.