Speaker
Description
SgrA* 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 MHD simulation to study the magnetic reconnection process which is on the accretion disk, and show the plasmoid merger and the shock wave during the magnetic reconnection. In our simulations, there are many plasmoids formed due to the magnetic reconnection, and these plasmoids consequently merge many times. It is found that the temperature-dependent diffusivity will cause more frequent merger of the plasmoids. The simulation results also show that the reconnection of magnetic field lines passes through a current sheet, which bifurcates into two pairs of slow shocks. 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.
