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Alfvén wave‐driven ionospheric mass outflow and electron precipitation during storms
Author(s) -
Hatch S. M.,
Chaston C. C.,
LaBelle J.
Publication year - 2016
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2016ja022805
Subject(s) - ionosphere , outflow , storm , atmospheric sciences , geomagnetic storm , magnetosphere , physics , geophysics , noon , flux (metallurgy) , daytime , solar wind , magnetic field , meteorology , chemistry , organic chemistry , quantum mechanics
We explore the global Alfvénic response of the transition region between the topside ionosphere and magnetosphere to geomagnetic storms. From superposed epoch and storm phase‐dependent analyses, it is found that subsequent to storm commencement the occurrence rate of Alfvénic field variations on electron inertial scales through this region increases by as much as a factor of 5 relative to prestorm levels. This increase is accompanied by order‐of‐magnitude enhancements in coincident energy deposition rates into the ionosphere and ion outflow rates into the magnetosphere, particularly near noon, premidnight, and on the dawn flank. During main phase on the dayside these waves shift to lower invariant latitudes (ILATs), expanding over a large range of ILATs and magnetic local times, where they are associated with significant enhancements in upward ion flux. Nightside storm‐enhanced occurrence probability of Alfvén waves and upward ion flux is lower than on the dayside, but the average precipitating electron energy flux is larger. There is also a localized region of intense ion outflow premidnight at low latitudes during storm main phase. Wave occurrence rates subside to prestorm levels about 20 h after storm commencement.