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Coupling the Solar-Wind/IMF to the Ionosphere through the High Latitude CuspsMagnetic merging is a primary means for coupling energy from the solar wind into the magnetosphere-ionosphere system. The location and nature of the process remain as open questions. By correlating measurements form diverse locations and using large-scale MHD models to put the measurements in context, it is possible to constrain out interpretations of the global and meso-scale dynamics of magnetic merging. Recent evidence demonstrates that merging often occurs at high latitudes in the vicinity of the cusps. The location is in part controlled by the clock angle in the interplanetary magnetic field (IMF) Y-Z plane. In fact, B(sub Y) bifurcated the cusp relative to source regions. The newly opened field lines may couple to the ionosphere at MLT locations of as much as 3 hr away from local noon. On the other side of noon the cusp may be connected to merging sites in the opposite hemisphere. In face, the small convection cell is generally driven by opposite hemisphere merging. B(sub X) controls the timing of the interaction and merging sites in each hemisphere, which may respond to planar features in the IMF at different times. Correlation times are variable and are controlled by the dynamics of the tilt of the interplanetary electric field phase plane. The orientation of the phase plane may change significantly on time scales of tens of minutes. Merging is temporally variable and may be occurring at multiple sites simultaneously. Accelerated electrons from the merging process excite optical signatures at the foot of the newly opened field lines. All-sky photometer observations of 557.7 nm emissions in the cusp region provide a "television picture" of the merging process and may be used to infer the temporal and spatial variability of merging, tied to variations in the IMF.
Document ID
20050040875
Acquisition Source
Headquarters
Document Type
Preprint (Draft being sent to journal)
Authors
Maynard, Nelson C.
(Mission Research Corp. Nashua, NH, United States)
Date Acquired
August 22, 2013
Publication Date
January 1, 2003
Subject Category
Solar Physics
Funding Number(s)
CONTRACT_GRANT: AFOSR-2311AS
CONTRACT_GRANT: NAG5-3182
CONTRACT_GRANT: NASW-01011
CONTRACT_GRANT: DTRA-45045
CONTRACT_GRANT: NASW-02017
CONTRACT_GRANT: NAG5-8135
Distribution Limits
Public
Copyright
Other

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