Quasi-cylindrical kinetic simulations of particle acceleration in relativistic magnetized jets

The mechanisms by which relativistic magnetized jets from AGN produce non-thermal particles and radiation remain a long-standing puzzle. Recent large-scale 3D particle-in-cell (PIC) simulations show that the onset of hydromagnetic instabilities in jets can lead to efficient non-thermal particle acceleration [1,2,3]. However, these simulations are computationally expensive, as they need to capture large dynamic ranges to understand how acceleration mechanisms might scale to and operate at astrophysically relevant system sizes.

Motivated by the natural cylindrical symmetry of jets, we explore the use of PIC simulations in quasi-cylindrical geometry [4], where fields and currents are decomposed in a truncated azimuthal basis, to carry out large dynamic range studies of particle acceleration in relativistic jets. We compare quasi-cylindrical and full-3D (cartesian) simulations of non-thermal particle acceleration driven by the kink instability [1]. By investigating numerical convergence properties, we determine the minimal number of azimuthal modes required to recover 3D results for different system sizes. We show that quasi-cylindrical PIC simulations offer a promising and efficient method of probing the 3D physics of particle acceleration in relativistic jets.

[1] Alves et al. 2018

[2] J. Develaar et al. 2020

[3] Ortuño-Macías et al. 2022

[4] Davidson et al. 2015