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Ion temperature anisotropy across a magnetotail reconnection jet.

ABSTRACT: A significant fraction of the energy released by magnetotail reconnection appears to go into ion heating, but this heating is generally anisotropic. We examine ARTEMIS dual-spacecraft observations of a long-duration magnetotail exhaust generated by antiparallel reconnection in conjunction with particle-in-cell simulations, showing spatial variations in the anisotropy across the outflow far (>100di ) downstream of the X line. A consistent pattern is found in both the spacecraft data and the simulations: While the total temperature across the exhaust is rather constant, near the boundaries Ti,|| dominates. The plasma is well above the firehose threshold within patchy spatial regions at |BX |?[0.1,0.5]B0, suggesting that the drive for the instability is strong and the instability is too weak to relax the anisotropy. At the midplane ( |BX|?0.1B0), Ti,?>Ti,|| and ions undergo Speiser-like motion despite the large distance from the X line.

SUBMITTER: Hietala H

PROVIDER: S-EPMC4950132 | biostudies-literature | 2015 Sep

REPOSITORIES: biostudies-literature

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Ion temperature anisotropy across a magnetotail reconnection jet.

Hietala H H Drake J F JF Phan T D TD Eastwood J P JP McFadden J P JP

Geophysical research letters 20150918 18

A significant fraction of the energy released by magnetotail reconnection appears to go into ion heating, but this heating is generally anisotropic. We examine ARTEMIS dual-spacecraft observations of a long-duration magnetotail exhaust generated by antiparallel reconnection in conjunction with particle-in-cell simulations, showing spatial variations in the anisotropy across the outflow far (>100di ) downstream of the X line. A consistent pattern is found in both the spac ...[more]

PMID: 27478283

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