Extreme ionospheric ion energization and electron heating in Alfv\ en waves in the storm-time inner magnetosphere

Author
Keywords
Abstract
We report measurements of energized outflowing/bouncing ionospheric ions and heated electrons in the inner magnetosphere during a geomagnetic storm. The ions arrive in the equatorial plane with pitch angles that increase with energy over a range from tens of eV to > 50 keV while the electrons are field-aligned up to ~1 keV. These particle distributions are observed during intervals of broadband low frequency electromagnetic field fluctuations consistent with a Doppler-shifted spectrum of kinetic Alfv\ en waves and kinetic field-line resonances. The fluctuations extend from L≈3 out to the apogee of the Van Allen Probes spacecraft at L≈6.5. They thereby span most of the L-shell range occupied by the ring current. These measurements suggest a model for ionospheric ion outflow and energization driven by dispersive Alfv\ en waves that may account for the large storm-time contribution of ionospheric ions to magnetospheric energy density.
Year of Publication
2015
Journal
Geophysical Research Letters
Date Published
12/2015
URL
http://doi.wiley.com/10.1002/2015GL066674http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002\%2F2015GL066674
DOI
10.1002/2015GL066674