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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Article number | A12228 |
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<mark>Journal publication date</mark> | 28/12/2011 |
<mark>Journal</mark> | Journal of Geophysical Research |
Volume | 116 |
Number of pages | 16 |
Pages (from-to) | - |
Publication Status | Published |
<mark>Original language</mark> | English |
For 15 high-speed-stream-driven geomagnetic activations (weak storms) in 2006-2007, the temporal behaviors of the outer electron radiation belt at geosynchronous orbit and the energetic-electron population of the magnetotail are compared via superposed-epoch averaging of data. The magnetotail measurements are obtained by using GPS-orbit measurements that magnetically map out into the magnetotail. Four temporal phases of high-speed-stream-driven storms are studied: (1) the pre-storm density decay of the electron-radiation belt, (2) the electron-radiation-belt density dropout near the time of storm onset, (3) the rapid density recovery a few hours after dropout, and (4) the heating of the electron radiation belt during the high-speed-stream-driven geomagnetic activity. In all four phases the behaviors of the outer electron radiation belt and of the energetic-electron population in the magnetotail are the same and simultaneous. The physical explanations for the behavior in phase 1 (decay), phase 2 (dropout), and phase 4 (heating) lie in the dipolar regions of the magnetosphere: hence for those three phases it is concluded that the temporal behavior of the energetic-electron population in the magnetotail mimics the behavior of the outer electron radiation belt. Behavior attributable to physical processes in the dipole is seen in the magnetotail energetic-electron population: this implies that the origin of the energetic-electron population of the magnetotail is "leakage" or "outward evaporation" from the outer electron radiation belt in the dipolar magnetosphere.