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Statistical characteristics of slow earthward and tailward flows in the plasma sheet
Author(s) -
Zhang L. Q.,
Baumjohann W.,
Wang J. Y.,
Rème H.,
Dunlop M. W.,
Chen T.
Publication year - 2015
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2015ja021354
Subject(s) - plasma sheet , isotropy , plasma , convection , anisotropy , reflection (computer programming) , ion , flow (mathematics) , geophysics , magnetic field , physics , atomic physics , condensed matter physics , mechanics , magnetosphere , optics , quantum mechanics , computer science , programming language
Abstract In this paper, we statistically analyzed and compared the earthward flow (EF) and the tailward flow (TF) in the plasma sheet. It is found that the properties of the EF/TF in the central plasma sheet (CPS) of β > 1 and the outer plasma sheet (OPS) of 0.1 < β < 1 are distinctly different. The main conclusions include that (1) the EFs occur in both the CPS and the OPS while the TFs mainly occur in the OPS, (2) both flows are dominantly convective in the CPS and parallel in the OPS, (3) in the CPS, the EF and the TF have similar characteristics, including their bulk velocities and ion densities and E y components. Both flows tend to have isotropic temperatures; (4) in the OPS, the EFs tend to have higher ion velocity, density, and E y than the TF. The EFs tend to have anisotropic temperatures, while the TFs tend to have more isotropic temperatures. As a whole, combined characteristics of the EF and the TF are consistent with (1) reflection at the “magnetic mirror point” near the Earth for parallel flows in the OPS and (2) bouncing off/back from the dipolar field closer to the Earth for convective flows in the CPS.