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Boundary layer plasma flows from high-latitude reconnection in the summer hemisphere for northward IMF: THEMIS multi-point observations

Hasegawa, H; McFadden, JP; Constantinescu, OD; Bogdanova, YV; Wang, J; Dunlop, MW; Angelopoulos, V; ... Shi, JK; + view all (2009) Boundary layer plasma flows from high-latitude reconnection in the summer hemisphere for northward IMF: THEMIS multi-point observations. Geophysical Research Letters , 36 , Article L15107. 10.1029/2009GL039410. Green open access

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Abstract

On 2008-07-11, the THEMIS spacecraft, separated both longitudinally and radially, traversed the dayside low-latitude boundary layer (LLBL) under extended northward IMF. They detected southward flows of magnetosheath plasma from magnetopause reconnection poleward of the northern cusp, which were cold-dense, and had southward velocity similar to 100 km/s and longitudinal extent >3 R-E. These features all agree with a global MHD simulation of the magnetosphere for similar conditions, in which under large geomagnetic dipole tilt, an LLBL forms via poleward-of-the-cusp reconnection first in the summer hemisphere and later in the other. Contrary to the simulation, however, the observed LLBL was mostly magnetically closed, characterized by balanced field-aligned and anti-field-aligned electron fluxes, and was less thick (<= 0.5 R-E). The former suggests comparable reconnection rate in both hemispheres, while the latter suggests the actual reconnection rate being lower, and/or the plasma transport toward the magnetotail being faster, than in the simulation. Citation: Hasegawa, H., et al. (2009), Boundary layer plasma flows from high-latitude reconnection in the summer hemisphere for northward IMF: THEMIS multi-point observations, Geophys. Res. Lett., 36, L15107, doi: 10.1029/2009GL039410.

Type: Article
Title: Boundary layer plasma flows from high-latitude reconnection in the summer hemisphere for northward IMF: THEMIS multi-point observations
Open access status: An open access version is available from UCL Discovery
DOI: 10.1029/2009GL039410
Publisher version: http://dx.doi.org/10.1029/2009GL039410
Language: English
Additional information: Copyright 2009 by the American Geophysical Union
Keywords: Interplanetary magnetic-field, Particle signatures, Magnetopause, Magnetometer, Instrument, Sheet, Model
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics
URI: https://discovery.ucl.ac.uk/id/eprint/162569
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