Open AccessCluster observations of collisionless Hall reconnection at high‐latitude magnetopause
Author(s) -
Zhang H.,
Zong Q.G.,
Fritz T. A.,
Fu S. Y.,
Schaefer S.,
Glassmeier K. H.,
Daly P. W.,
Rème H.,
Balogh A.
Publication year - 2008
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2007ja012769
Subject(s) - magnetopause , current sheet , magnetic reconnection , magnetosheath , physics , interplanetary magnetic field , plasma sheet , astrophysics , geophysics , magnetic field , solar wind , magnetosphere , magnetohydrodynamics , quantum mechanics
The first in situ observation of collisionless Hall reconnection in the high‐latitude region when the interplanetary magnetic field (IMF) B y dominates is reported in this paper. On 23 March 2002, Cluster crossed the magnetopause current sheet when it traveled outbound in the Northern Hemisphere. The interface between the cusp and the magnetosheath is clearly associated with sharp transitions of the magnetic field and plasma moments. These variations suggest that the interface is a clear current sheet with a thickness of 218 km. Energetic electrons, protons, helium, and oxygen ions were observed and their intensity peaked at this current sheet. During that time period, the IMF B z is around zero and the IMF B y component dominates. The geometry of the magnetic field preferred B y reconnection. The bipolar signature in the magnetic field observed by Cluster is consistent with Hall effects in the reconnection process. Characteristics of three B y reconnection events are presented in this paper.