Open AccessCusp observations of high‐ and low‐latitude reconnection for northward interplanetary magnetic field
Author(s) -
Fuselier S. A.,
Trattner K. J.,
Petrinec S. M.
Publication year - 2000
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 - 10.1029/1999ja900422
Subject(s) - magnetic reconnection , interplanetary magnetic field , physics , magnetosheath , geophysics , magnetopause , solar wind , cusp (singularity) , magnetosphere , polar , astrophysics , magnetic field , astronomy , geometry , mathematics , quantum mechanics
Polar/Toroidal Imaging Mass Angle Spectrograph (TIMAS) observations in the cusp reveal evidence of both high‐ and low‐latitude reconnection during high solar wind dynamic pressure, northward interplanetary magnetic field (IMF) intervals. Under these restrictive conditions, the magnetic field observed by the Polar/Magnetic Fields Investigation in the northern cusp often rotates from lobe‐like orientations ( B Z <0, B x >0) to dayside magnetospheric‐like orientations ( B z >0, B x <0). Proton distributions observed when the magnetic field has a magnetospheric‐like orientation are consistent with either reconnection poleward of the cusp at high‐latitudes or reconnection equatorward of the cusp at lower latitudes. Transitions from one type of proton distribution to another as the field rotates from lobe‐like to dayside magnetospheric‐like orientations indicate sunward (poleward) convection of the reconnected magnetic field for reconnection poleward (equatorward) of the cusp. A survey of 17 intervals of high solar wind dynamic pressure and northward IMF indicates that these two reconnection topologies occur with approximately equal probability and that reconnection equatorward of the cusp favors small angles between the magnetosheath and dayside magnetospheric magnetic fields.