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Title: Particle acceleration during magnetic reconnection in a low-beta pair plasma

Plasma energization through magnetic reconnection in the magnetically dominated regime featured by low plasma beta (β=8πnkT0/B 2 <<1) and/or high magnetization (σ=B 2/(4πnmc 2)>>1) is important in a series of astrophysical systems such as solar flares, pulsar wind nebula, and relativistic jets from black holes. In this paper, we review the recent progress on kinetic simulations of this process and further discuss plasma dynamics and particle acceleration in a low-β reconnection layer that consists of electron–positron pairs. We also examine the effect of different initial thermal temperatures on the resulting particle energy spectra. While earlier papers have concluded that the spectral index is smaller for higher σ, our simulations show that the spectral index approaches p = 1 for sufficiently low plasma β, even if σ~1. Since this predicted spectral index in the idealized limit is harder than most observations, it is important to consider effects that can lead to a softer spectrum such as open boundary simulations. Here, we also remark that the effects of three-dimensional reconnection physics and turbulence on reconnection need to be addressed in the future.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [3]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Univ. of Alabama in Huntsville, Huntsville, AL (United States)
  3. NASA Goddard Space Flight Center, Greenbelt, MD (United States)
Publication Date:
Report Number(s):
LA-UR-16-21885
Journal ID: ISSN 1070-664X
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 5; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Laboratory Directed Research and Development (LDRD) Program
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; astronomy and astrophysics
OSTI Identifier:
1338803
Alternate Identifier(s):
OSTI ID: 1420672