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(Reference retrieved automatically from Google Scholar through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Particle Acceleration in Turbulence and Weakly Stochastic Reconnection

Full text
Author(s):
Kowal, Grzegorz [1] ; de Gouveia Dal Pino, Elisabete M. [1] ; Lazarian, A. [2]
Total Authors: 3
Affiliation:
[1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508090 Sao Paulo - Brazil
[2] Univ Wisconsin, Dept Astron, Madison, WI 53706 - USA
Total Affiliations: 2
Document type: Journal article
Source: Physical Review Letters; v. 108, n. 24, p. 241102, 2012.
Web of Science Citations: 49
Abstract

In this Letter we analyze the energy distribution evolution of test particles injected in three dimensional (3D) magnetohydrodynamic (MHD) simulations of different magnetic reconnection configurations. When considering a single Sweet-Parker topology, the particles accelerate predominantly through a first-order Fermi process, as predicted in [3] and demonstrated numerically in [8]. When turbulence is included within the current sheet, the acceleration rate is highly enhanced, because reconnection becomes fast and independent of resistivity [4,11] and allows the formation of a thick volume filled with multiple simultaneously reconnecting magnetic fluxes. Charged particles trapped within this volume suffer several head-on scatterings with the contracting magnetic fluctuations, which significantly increase the acceleration rate and results in a first-order Fermi process. For comparison, we also tested acceleration in MHD turbulence, where particles suffer collisions with approaching and receding magnetic irregularities, resulting in a reduced acceleration rate. We argue that the dominant acceleration mechanism approaches a second order Fermi process in this case. (AU)

FAPESP's process: 06/50654-3 - Investigation of high energy and plasma astrophysics phenomena: theory, observation, and numerical simulations
Grantee:Elisabete Maria de Gouveia Dal Pino
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 09/50053-8 - Magnetic reconnection and particle acceleration in astrophysical sources and diffuse media
Grantee:Grzegorz Kowal
Support Opportunities: Scholarships in Brazil - Post-Doctoral