Skip to main content

Relativistic reconnection: An efficient source of non-thermal particles

Author(s): Sironi, L; Spitkovsky, Anatoly

To refer to this page use:
Abstract: In magnetized astrophysical outflows, the dissipation of field energy into particle energy via magnetic reconnection is often invoked to explain the observed non-thermal signatures. By means of two- and three-dimensional particle-in-cell simulations, we investigate anti-parallel reconnection in magnetically dominated electron-positron plasmas. Our simulations extend to unprecedentedly long temporal and spatial scales, so we can capture the asymptotic state of the system beyond the initial transients, and without any artificial limitation by the boundary conditions. At late times, the reconnection layer is organized into a chain of large magnetic islands connected by thin X-lines. The plasmoid instability further fragments each X-line into a series of smaller islands, separated by X-points. At the X-points, the particles become unmagnetized and they get accelerated along the reconnection electric field. We provide definitive evidence that the late-time particle spectrum integrated over the whole reconnection region is a power law whose slope is harder than -2 for magnetizations σ ≳ 10. Efficient particle acceleration to non-thermal energies is a generic by-product of the long-term evolution of relativistic reconnection in both two and three dimensions. In three dimensions, the drift-kink mode corrugates the reconnection layer at early times, but the long-term evolution is controlled by the plasmoid instability which facilitates efficient particle acceleration, analogous to the two-dimensional physics. Our findings have important implications for the generation of hard photon spectra in pulsar winds and relativistic astrophysical jets.
Publication Date: 18-Feb-2014
Electronic Publication Date: 1-Mar-2014
Citation: Sironi, L, Spitkovsky, A. (2014). Relativistic reconnection: An efficient source of non-thermal particles. Astrophysical Journal Letters, 783 (1), 10.1088/2041-8205/783/1/L21
DOI: doi:10.1088/2041-8205/783/1/L21
ISSN: 2041-8205
EISSN: 2041-8213
Related Item:
Type of Material: Journal Article
Journal/Proceeding Title: Astrophysical Journal Letters
Version: Final published version. Article is made available in OAR by the publisher's permission or policy.

Items in OAR@Princeton are protected by copyright, with all rights reserved, unless otherwise indicated.