References

ANGEO

Annales Geophysicae

ANGEO

Ann. Geophys.

1432-0576

Copernicus Publications

Göttingen, Germany

10.5194/angeo-28-849-2010

Low altitude energetic electron lifetimes after enhanced magnetic activity as deduced from SAC-C and DEMETER data

Benck

¹ Mazzino

² Cyamukungu

¹ Cabrera

¹ Pierrard

¹ ³

Center for Space Radiations (CSR), Chemin du Cyclotron, 2, 1348 Louvain-la-Neuve, Belgium

University of Alberta, Department of Physics, 11322 – 89 Avenue, Edmonton Alberta, Canada

Belgian Institute for Space Aeronomy (BISA), Ringlaan-3-Avenue Circulaire, 1180 Brussels, Belgium

22 03 2010

28 3 849 859

2010

This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/

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When flux enhancements of energetic electrons are produced as a consequence of geomagnetic storm occurrence, they tend to vanish gradually when the magnetic activity calms down and the fluxes decay to quiet-time levels. We use SAC-C and DEMETER low altitude observations to estimate the energetic electron lifetimes (E=0.16–1.4 MeV, L=1.6–5, B=0.22–0.46 G) and compare the decay rates to those observed at high altitude. While crossing the radiation belts at high latitude, the SAC-C and DEMETER instruments sample particles with small equatorial pitch angles (αeq<18° for L>2.5) whereas the comparison is done with other satellite data measured mainly in the equatorial plane (for αeq>75°). While in the inner belt and in the slot region no significant lifetime differences are observed from the data sets with different αeq, in the outer belt, for the least energetic electrons (<500 keV), the lifetimes are up to ~3 times larger for the electrons with the equatorial pitch-angle close to the loss cone than for those mirroring near the equator. The difference decreases with increasing energy and vanishes for energies of about 1 MeV.

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