Proton temperature anisotropy and magnetic reconnection in the solar wind: effects of kinetic instabilities on current sheet stability

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Title: Proton temperature anisotropy and magnetic reconnection in the solar wind: effects of kinetic instabilities on current sheet stability
Authors: Matteini, L
Landi, S
Velli, M
Matthaeus, WH
Item Type: Journal Article
Abstract: We investigate the role of kinetic instabilities driven by a proton anisotropy on the onset of magnetic reconnection by means of two-dimensional hybrid simulations. The collisionless tearing of a current sheet is studied in the presence of a proton temperature anisotropy in the surrounding plasma. Our results confirm that anisotropic protons within the current sheet region can significantly enhance/stabilize the tearing instability of the current. Moreover, fluctuations associated with linear instabilities excited by large proton temperature anisotropies can significantly influence the stability of the plasma and perturb the current sheets, triggering the tearing instability. We find that such a complex coupling leads to a faster tearing evolution in the $T_\perp >T_\Vert$ regime when an ion-cyclotron instability is generated by the anisotropic proton distribution functions. On the contrary, in the presence of the opposite anisotropy, fire-hose fluctuations excited by the unstable background protons with $T_\Vert <T_\perp$ are not able to efficiently destabilize current sheets, which remain stable for a long time after fire-hose saturation. We discuss possible influences of this novel coupling on the solar wind and heliospheric plasma dynamics.
Issue Date: 1-Feb-2013
Date of Acceptance: 6-Dec-2012
URI: http://hdl.handle.net/10044/1/74170
DOI: https://doi.org/10.1088/0004-637X/763/2/142
ISSN: 0004-637X
Publisher: American Astronomical Society
Journal / Book Title: The Astrophysical Journal: an international review of astronomy and astronomical physics
Volume: 763
Issue: 2
Copyright Statement: © 2013. The American Astronomical Society. All rights reserved.
Sponsor/Funder: Science and Technology Facilities Council (STFC)
Science and Technology Facilities Council [2006-2012]
Funder's Grant Number: ST/K001051/1
ST/K001051/1
Keywords: Science & Technology
Physical Sciences
Astronomy & Astrophysics
instabilities
magnetic reconnection
methods: numerical
plasmas
solar wind
VELOCITY DISTRIBUTION FUNCTION
TEARING INSTABILITY
NEUTRAL SHEET
PLASMA INSTABILITIES
HYBRID SIMULATIONS
HOSE INSTABILITY
FIELD
MECHANISM
DYNAMICS
1-AU
Science & Technology
Physical Sciences
Astronomy & Astrophysics
instabilities
magnetic reconnection
methods: numerical
plasmas
solar wind
VELOCITY DISTRIBUTION FUNCTION
TEARING INSTABILITY
NEUTRAL SHEET
PLASMA INSTABILITIES
HYBRID SIMULATIONS
HOSE INSTABILITY
FIELD
MECHANISM
DYNAMICS
1-AU
physics.space-ph
physics.space-ph
astro-ph.SR
physics.plasm-ph
0201 Astronomical and Space Sciences
0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics
0306 Physical Chemistry (incl. Structural)
Astronomy & Astrophysics
Publication Status: Published
Article Number: 142
Online Publication Date: 2013-01-17
Appears in Collections:Space and Atmospheric Physics
Physics



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