Publication Date:
2015-08-25
Description:
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 anti-parallel reconnection in conjunction with Particle-In-Cell simulations, showing spatial variations in the anisotropy across the outflow far (〉 100 d i ) downstream of the X-line. A consistent pattern is found in both the spacecraft data and the simulations: Whilst the total temperature across the exhaust is rather constant, near the boundaries T i ,|| dominates. The plasma is well-above the firehose threshold within patchy spatial regions at | B X | ∈ [0.1, 0.5] B 0 , suggesting that the drive for the instability is strong and the instability is too weak to relax the anisotropy. At the mid-plane (| B X |0.1 B 0 ), T i ,⊥ 〉 T i ,|| and ions undergo Speiser-like motion despite the large distance from the X-line.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
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