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arXiv · 1307.2071

TEC evidence for near-equatorial energy deposition by 30-keV electrons in the topside ionosphere

A. V. Suvorova·A. V. Dmitriev·L. -C. Tsai·V. E. Kunitsyn·E. S. Andreeva·I. A. Nesterov·L. L. Lazutin
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Abstract

Observations of energetic electrons (10 - 300 keV) by NOAA/POES and DMSP satellites at heights <1000 km during the period from 1999 to 2010 allowed finding abnormal intense fluxes of ~10^6 - 10^7 cm-2 s-1 sr-1 for quasi-trapped electrons appearing within the forbidden zone of low latitudes over the African, Indo-China, and Pacific regions. Extreme fluxes appeared often in the early morning and persisted for several hours during the maximum and recovery phase of geomagnetic storms. We analyzed nine storm-time events when extreme electron fluxes first appeared in the Eastern Hemisphere, then drifted further eastward toward the South-Atlantic Anomaly. Using the electron spectra, we estimated the possible ionization effect produced by quasi-trapped electrons in the topside ionosphere. The estimated ionization was found to be large enough to satisfy observed storm-time increases in the ionospheric total electron content determined for the same spatial and temporal ranges from global ionospheric maps. Additionally, extreme fluxes of quasi-trapped electrons were accompanied by the significant elevation of the low-latitude F-layer obtained from COSMIC/FORMOSAT-3 radio occultation measurements. We suggest that the storm-time ExB drift of energetic electrons from the inner radiation belt is an important driver of positive ionospheric storms within low-latitude and equatorial regions.

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A. V. Suvorova, A. V. Dmitriev, L. -C. Tsai, V. E. Kunitsyn, E. S. Andreeva, I. A. Nesterov, L. L. Lazutin. 2013-07-08. TEC evidence for near-equatorial energy deposition by 30-keV electrons in the topside ionosphere. https://doi.org/10.1002/jgra.50439

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