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Uncovering the nonadiabatic response of geosynchronous electrons to geomagnetic disturbance

Journal of Geophysical Research

By:
, ,
DOI: 10.1029/2012JA017543

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Abstract

We describe an energy spectrum method for scaling electron integral flux, which is measured at a constant energy, to phase space density at a constant value of the first adiabatic invariant which removes much of the variation due to reversible adiabatic effects. Applying this method to nearly a solar cycle (1995 - 2006) of geosynchronous electron integral flux (E>2.0MeV) from the GOES satellites, we see that much of the diurnal variation in electron phase space density at constant energy can be removed by the transformation to phase space density at constant μ (4000 MeV/G). This allows us a clearer picture of underlying non-adiabatic electron population changes due to geomagnetic activity. Using scaled phase space density, we calculate the percentage of geomagnetic storms resulting in an increase, decrease or no change in geosynchronous electrons as 38%, 7%, and 55%, respectively. We also show examples of changes in the electron population that may be different than the unscaled fluxes alone suggest. These examples include sudden electron enhancements during storms which appear during the peak of negative Dst for μ-scaled phase space density, contrary to the slow increase seen during the recovery phase for unscaled phase space density for the same event.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Uncovering the nonadiabatic response of geosynchronous electrons to geomagnetic disturbance
Series title:
Journal of Geophysical Research
DOI:
10.1029/2012JA017543
Volume
117
Issue:
A10
Year Published:
2012
Language:
English
Publisher:
American Geophysical Union
Contributing office(s):
Geologic Hazards Science Center
Description:
A10215, 7 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article