# Rotation and toroidal magnetic field effects on the stability of two-component jets

## TL;DR

This study investigates how rotation and toroidal magnetic fields influence the stability of two-component astrophysical jets, revealing that magnetic fields above a certain magnetization threshold can stabilize jets against instabilities.

## Contribution

It extends previous jet stability studies by incorporating non-zero toroidal magnetic fields and analyzing their effect on jet stability and dynamics.

## Key findings

- Toroidal magnetic fields above $\sigma hickapprox 0.01$ stabilize jets.
- Magnetization affects the average Lorentz factor and jet radius.
- Increased magnetization alters jet evolution and stability trends.

## Abstract

Several observations of astrophysical jets show evidence of a structure in the direction perpendicular to the jet axis, leading to the development of "spine & sheath" models of jets. Most studies focus on a two-component jet consisting of a highly relativistic inner jet and a slower - but still relativistic - outer jet surrounded by an unmagnetized environment. These jets are believed to be susceptible to a relativistic Rayleigh-Taylor-type instability, depending on the effective inertia ratio of the two components. We extend previous studies by taking into account the presence of a non-zero toroidal magnetic field. Different values of magnetization are examined, to detect possible differences in the evolution and stability of the jet. We find that the toroidal field, above a certain level of magnetization $\sigma$, roughly equal to 0.01, can stabilize the jet against the previously mentioned instabilities and that there is a clear trend in the behaviour of the average Lorentz factor and the effective radius of the jet when we continuously increase the magnetization. The simulations are performed using the relativistic MHD module from the open source, parallel, grid adaptive, MPI-AMRVAC code.