Efficient production of high-energy nonthermal particles during magnetic reconnection in a magnetically dominated ion-electron plasma [electronic resource].
- Published:
- Washington, D.C. : United States. Dept. of Energy, 2016.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy - Physical Description:
- Article numbers L9 : digital, PDF file
- Additional Creators:
- Los Alamos National Laboratory
United States. Department of Energy
United States. Department of Energy. Office of Scientific and Technical Information - Access Online:
- www.osti.gov
- Summary:
- Magnetic reconnection is a leading mechanism for dissipating magnetic energy and accelerating nonthermal particles in Poynting-flux-dominated flows. We investigate nonthermal particle acceleration during magnetic reconnection in a magnetically dominated ion–electron plasma using fully kinetic simulations. For an ion–electron plasma with a total magnetization of ${\sigma }_{0}={B}^{2}/(4\pi n({m}_{i}+{m}_{e}){c}^{2})$, the magnetization for each species is ${\sigma }_{i}\sim {\sigma }_{0}$ and ${\sigma }_{e}\sim ({m}_{i}/{m}_{e}){\sigma }_{0}$, respectively. We have studied the magnetically dominated regime by varying σe = 103–105 with initial ion and electron temperatures ${T}_{i}={T}_{e}=5-20{m}_{e}{c}^{2}$ and mass ratio ${m}_{i}/{m}_{e}=1-1836$. Our results demonstrate that reconnection quickly establishes power-law energy distributions for both electrons and ions within several (2–3) light-crossing times. For the cases with periodic boundary conditions, the power-law index is $1\lt s\lt 2$ for both electrons and ions. The hard spectra limit the power-law energies for electrons and ions to be ${\gamma }_{{be}}\sim {\sigma }_{e}$ and ${\gamma }_{{bi}}\sim {\sigma }_{i}$, respectively. The main acceleration mechanism is a Fermi-like acceleration through the drift motions of charged particles. When comparing the spectra for electrons and ions in momentum space, the spectral indices sp are identical as predicted in Fermi acceleration. We also find that the bulk flow can carry a significant amount of energy during the simulations. Finally, we discuss the implication of this study in the context of Poynting-flux dominated jets and pulsar winds, especially the applications for explaining nonthermal high-energy emissions.
- Subject(s):
- Note:
- Published through SciTech Connect.
02/03/2016.
"la-ur--15-28215"
The Astrophysical Journal. Letters 818 1 ISSN 2041-8213 AM
Fan Guo; Xiaocan Li; Hui Li; William Daughton; Bing Zhang; Nicole Lloyd-Ronning; Yi-Hsin Liu; Haocheng Zhang; Wei Deng. - Funding Information:
- AC52-06NA25396
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