HR: 16:00h
AN: SM34A-03    [Abstracts]
TI: Dual Lobe Reconnection During Northward IMF
AU: * McFadden, J P
EM: mcfadden@ssl.berkeley.edu
AF: Space Sciences Lab University of California, 7 Gauss Way, Berkeley, CA 94720 United States
AU: Fazakerley, A
EM: anf@mssl.ucl.ac.uk
AF: Mullard Space Science Laboratory Univ. College London,, Holmbury St. Mary, Dorking, Surrey,, RH5 6NT United Kingdom
AU: Balogh, A
EM: a.balogh@ic.ac.uk
AF: The Blackett Laboratory, Imperial College,, Prince Consort Road, London, United Kingdom
AU: Reme, H
EM: Henri.Reme@cesr.fr
AF: CESR/CNRS, 9 Avenue du Colonel Roche, B.P. 4346, F-31028, Toulouse, France
AB: Cluster and Polar high latitude observations provide evidence that dual lobe reconnection during northward IMF is common, and that the magnetopause boundary layers are primarily on closed magnetic field lines at these times. This contrasts with the open MSBL/LLBL model of Fuselier et al. (JGR, 1995) which used low latitude observations to deduce the structure of the magnetopause. The primary difficulty with the low latitude observations is the unambiguous identification of the magnetopause due to the lack of strong magnetic shear during northward IMF. The open MSBL/LLBL model also requires some unknown mechanism to heat the electrons at the magnetopause even during low shear conditions that fail to heat the ions. This paper presents an alternative model of the low shear magnetopause. Dual lobe reconnection is favored because lobe reconnection requires a plasma depletion layer so the magnetosheath flow is sub-Alfvenic. The depletion layer initially forms at the sub-solar region after the field line has draped, and spreads toward both lobes simultaneously. Sub-solar draping assures that the magnetic shear in both lobes is about the same leading to nearly identical conditions in both hemispheres. Reconnection will not be simultaneous, but is favored to occur in both hemispheres due to similar conditions. Cluster observations will be presented to support this model.
DE: 2700 MAGNETOSPHERIC PHYSICS
DE: 2724 Magnetopause, cusp, and boundary layers
DE: 2740 Magnetospheric configuration and dynamics
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2005 Joint Assembly