Non-relativistic and relativistic magnetic reconnection with the effects of optically thin synchrotron cooling

PASJ: Publications of the Astronomical Society of Japan

Takahashi, Hiroyuki R¹  Shibata, Kazunari²  Takeshige, Satoshi³ 

[1] Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto, Kyoto 606-8502, Japan;Engineering Science Laboratory, College of Engineering, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8051, Japan;Kwasan and Hida Observatories, Kyoto University, 17 Ohmine-cho, Kita Kwazan, Yamashina, Kyoto, Kyoto 607-8471, Japan

关键词: magnetic reconnection;    relativistic processes;    plasmas;    magnetohydrodynamics (MHD);   

DOI  :  10.1093/pasj/psz038

学科分类：天文学(综合)

来源: Oxford University Press

【 摘 要 】

We performed special relativistic resistive magnetohydrodynamic simulations of Petscheck-type magnetic reconnection including an optically thin synchrotron cooling. The magnetization parameter, σ0, which is the ratio of Poynting flux to mass flux in the upstream plasma, is taken to be 0.01 and 3. For the non-relativistic plasma (σ0 = 0.01), the radiative cooling subtracts thermal energy mainly in the upstream plasma and a plasma is strongly compressed at the slow shock. The cooling in the post-shock region and plasmoid also reduces the thermal energy and it forms a narrower outflow. The reconnection rate slightly increases as a result of the radiative cooling, since the plasma beta in the inflow region becomes small. The effect of decreasing thermal energy in the outflow region is more prominent for the relativistic plasma (σ0 = 3). In this case, the outflow temperature increases and the plasma internal energy becomes comparable to the plasma rest mass energy. The subtraction of this thermal energy by radiative cooling leads to a decrease in plasma inertia and the outflows are more accelerated than without radiative cooling. The reconnection rate is also enhanced by its Lorentz contraction effect. For both non-relativistic and relativistic simulations, it is concluded that the reconnection rate is determined by the plasma beta in the inflow region.

【 授权许可】

CC BY