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Title: MAGNETOHYDRODYNAMIC SIMULATIONS OF RECONNECTION AND PARTICLE ACCELERATION: THREE-DIMENSIONAL EFFECTS

Abstract

Magnetic fields can change their topology through a process known as magnetic reconnection. This process in not only important for understanding the origin and evolution of the large-scale magnetic field, but is seen as a possibly efficient particle accelerator producing cosmic rays mainly through the first-order Fermi process. In this work we study the properties of particle acceleration inserted in reconnection zones and show that the velocity component parallel to the magnetic field of test particles inserted in magnetohydrodynamic (MHD) domains of reconnection without including kinetic effects, such as pressure anisotropy, the Hall term, or anomalous effects, increases exponentially. Also, the acceleration of the perpendicular component is always possible in such models. We find that within contracting magnetic islands or current sheets the particles accelerate predominantly through the first-order Fermi process, as previously described, while outside the current sheets and islands the particles experience mostly drift acceleration due to magnetic field gradients. Considering two-dimensional MHD models without a guide field, we find that the parallel acceleration stops at some level. This saturation effect is, however, removed in the presence of an out-of-plane guide field or in three-dimensional models. Therefore, we stress the importance of the guide field and fully three-dimensionalmore » studies for a complete understanding of the process of particle acceleration in astrophysical reconnection environments.« less

Authors:
;  [1]
  1. Department of Astronomy, University of Wisconsin, 475 North Charter Street, Madison, WI 53706 (United States)
Publication Date:
OSTI Identifier:
21578391
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 735; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/735/2/102; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; MAGNETIC FIELDS; MAGNETIC ISLANDS; MAGNETIC RECONNECTION; MAGNETOHYDRODYNAMICS; PARTICLES; SIMULATION; THREE-DIMENSIONAL CALCULATIONS; TWO-DIMENSIONAL CALCULATIONS; FLUID MECHANICS; HYDRODYNAMICS; MAGNETIC FIELD CONFIGURATIONS; MECHANICS

Citation Formats

Kowal, Grzegorz, De Gouveia Dal Pino, E. M., and Lazarian, A. MAGNETOHYDRODYNAMIC SIMULATIONS OF RECONNECTION AND PARTICLE ACCELERATION: THREE-DIMENSIONAL EFFECTS. United States: N. p., 2011. Web. doi:10.1088/0004-637X/735/2/102.
Kowal, Grzegorz, De Gouveia Dal Pino, E. M., & Lazarian, A. MAGNETOHYDRODYNAMIC SIMULATIONS OF RECONNECTION AND PARTICLE ACCELERATION: THREE-DIMENSIONAL EFFECTS. United States. https://doi.org/10.1088/0004-637X/735/2/102
Kowal, Grzegorz, De Gouveia Dal Pino, E. M., and Lazarian, A. 2011. "MAGNETOHYDRODYNAMIC SIMULATIONS OF RECONNECTION AND PARTICLE ACCELERATION: THREE-DIMENSIONAL EFFECTS". United States. https://doi.org/10.1088/0004-637X/735/2/102.
@article{osti_21578391,
title = {MAGNETOHYDRODYNAMIC SIMULATIONS OF RECONNECTION AND PARTICLE ACCELERATION: THREE-DIMENSIONAL EFFECTS},
author = {Kowal, Grzegorz and De Gouveia Dal Pino, E. M. and Lazarian, A},
abstractNote = {Magnetic fields can change their topology through a process known as magnetic reconnection. This process in not only important for understanding the origin and evolution of the large-scale magnetic field, but is seen as a possibly efficient particle accelerator producing cosmic rays mainly through the first-order Fermi process. In this work we study the properties of particle acceleration inserted in reconnection zones and show that the velocity component parallel to the magnetic field of test particles inserted in magnetohydrodynamic (MHD) domains of reconnection without including kinetic effects, such as pressure anisotropy, the Hall term, or anomalous effects, increases exponentially. Also, the acceleration of the perpendicular component is always possible in such models. We find that within contracting magnetic islands or current sheets the particles accelerate predominantly through the first-order Fermi process, as previously described, while outside the current sheets and islands the particles experience mostly drift acceleration due to magnetic field gradients. Considering two-dimensional MHD models without a guide field, we find that the parallel acceleration stops at some level. This saturation effect is, however, removed in the presence of an out-of-plane guide field or in three-dimensional models. Therefore, we stress the importance of the guide field and fully three-dimensional studies for a complete understanding of the process of particle acceleration in astrophysical reconnection environments.},
doi = {10.1088/0004-637X/735/2/102},
url = {https://www.osti.gov/biblio/21578391}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 735,
place = {United States},
year = {Sun Jul 10 00:00:00 EDT 2011},
month = {Sun Jul 10 00:00:00 EDT 2011}
}