Polarization Signatures of Kink Instabilities in the Blazar Emission Region from Relativistic Magnetohydrodynamic Simulations

TL;DR

This study uses relativistic MHD simulations to model how kink instabilities in blazar jets produce observable polarization signatures and flares, providing insights into jet magnetic structures.

Contribution

It presents the first comprehensive polarization-dependent radiation modeling of kink instabilities in blazar jets based on RMHD simulations, linking magnetic topology to observable signatures.

Findings

Kink instabilities can cause strong flares with polarization angle swings.

The polarization signatures from kink instabilities align better with observations than shock models.

Kink instabilities may be common in jet environments, converting magnetic energy into flares and polarization variations.

Abstract

Kink instabilities are likely to occur in the current-carrying magnetized plasma jets. Recent observations of the blazar radiation and polarization signatures suggest that the blazar emission region may be considerably magnetized. While the kink instability has been studied with first-principle magnetohydrodynamic (MHD) simulations, the corresponding time-dependent radiation and polarization signatures have not been investigated. In this paper, we perform comprehensive polarization-dependent radiation modeling of the kink instability in the blazar emission region based on relativistic MHD (RMHD) simulations. We find that the kink instability may give rise to strong flares with polarization angle (PA) swings or weak flares with polarization fluctuations, depending on the initial magnetic topology and magnetization. These findings are consistent with observations. Compared with the shock model, the kink model generates polarization signatures that are in better agreement with the general polarization observations. Therefore, we suggest that kink instabilities may widely exist in the jet environment, and provide an efficient way to convert the magnetic energy and produce multiwavelength flares and polarization variations.