Shock waves in the magnetic reconnection in the flares on the accretion disk of the SGR~A*

TL;DR

This study uses simulations to demonstrate that magnetic reconnection and shock waves in the accretion disk of Sgr A* can heat plasma and explain the observed episodic flares.

Contribution

The paper introduces a simulation model showing shock wave formation during magnetic reconnection in accretion disks near Sgr A*, explaining flare brightening.

Findings

Shock waves bifurcate into slow shocks during reconnection.

Shock heating is more effective at low plasma densities.

Simulation supports magnetic reconnection as a flare mechanism.

Abstract

Sgr~A* often shows bright, episodic flares observationally, the mechanism of the flares intermittent brightening is not very clear. Many people believe the flares may formed by the non-thermal particles, which can be a consequence of the magnetic reconnection and shock waves. In this work, we use the larger magnetic loop in the presence of pseudo-Newtonian potential which mimics general relativistic effects. The simulation results show that the reconnection of magnetic field lines passes through a current sheet, which bifurcates into two pairs of slow shocks. We also find the shock waves heat the plasma, especially when the plasma density is low. The shock wave heating effect by the magnetic reconnection is confirmed by the simulation results, and thus the process of instantaneous brightening of the flares on the accretion disk can be explained.