期刊
ASTROPHYSICAL JOURNAL
卷 806, 期 2, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/806/2/167
关键词
acceleration of particles; galaxies: jets; gamma-ray burst: general; magnetic reconnection; pulsars: general; relativistic processes
资金
- DOE through LDRD program at LANL
- DOE/OFES
- CMSO
- NASA through Heliospheric Theory Program
- NSF [OCI 07-25070]
- Direct For Mathematical & Physical Scien
- Division Of Physics [0821899] Funding Source: National Science Foundation
Magnetic reconnection is thought to be the driver for many explosive phenomena in the universe. The energy release and particle acceleration during reconnection have been proposed as a mechanism for producing high-energy emissions and cosmic rays. We carry out two- and three-dimensional (3D) kinetic simulations to investigate relativistic magnetic reconnection and the associated particle acceleration. The simulations focus on electron-positron plasmas starting with a magnetically dominated, force-free current sheet (sigma equivalent to B-2/(4 pi n(e)m(e)c(2)) >> 1). For this limit, we demonstrate that relativistic reconnection is highly efficient at accelerating particles through a first-order Fermi process accomplished by the curvature drift of particles along the electric field induced by the relativistic flows. This mechanism gives rise to the formation of hard power-law spectra f proportional to (gamma - 1)(-p) and approaches p = 1 for sufficiently large sigma and system size. Eventually most of the available magnetic free energy is converted into nonthermal particle kinetic energy. An analytic model is presented to explain the key results and predict a general condition for the formation of power-law distributions. The development of reconnection in these regimes leads to relativistic inflow and outflow speeds and enhanced reconnection rates relative to nonrelativistic regimes. In the 3D simulation, the interplay between secondary kink and tearing instabilities leads to strong magnetic turbulence, but does not significantly change the energy conversion, reconnection rate, or particle acceleration. This study suggests that relativistic reconnection sites are strong sources of nonthermal particles, which may have important implications for a variety of high-energy astrophysical problems.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据