Stability of three-dimensional relativistic jets: implications for jet collimation

TL;DR

This paper uses 3D numerical simulations to investigate the stability of relativistic jets, confirming that resonant modes in sheared flows may explain their long-term collimation despite Kelvin-Helmholtz instabilities.

Contribution

It extends previous 2D stability studies to 3D, demonstrating the importance of resonant modes in jet collimation through advanced relativistic hydrodynamics simulations.

Findings

Resonant modes are significant in jet stability.

3D simulations confirm 2D stability results.

Long-term collimation may be due to resonant mode growth.

Abstract

The stable propagation of jets in FRII sources is remarkable if one takes into account that large-scale jets are subjected to potentially highly disruptive three-dimensional (3D) Kelvin-Helmholtz instabilities. Numerical simulations can address this problem and help clarify the causes of this remarkable stability. Following previous studies of the stability of relativistic flows in two dimensions (2D), it is our aim to test and extend the conclusions of such works to three dimensions. We present numerical simulations for the study of the stability properties of 3D, sheared, relativistic flows. This work uses a fully parallelized code Ratpenat that solves equations of relativistic hydrodynamics in 3D. The results of the present simulations confirm those in 2D. We conclude that the growth of resonant modes in sheared relativistic flows could be important in explaining the long-term collimation of extragalactic jets.