TY - JOUR

T1 - Evolution of the magnetotail energetic-electron population during high-speed-stream-driven storms: Evidence for the leakage of the outer electron radiation belt into the Earth's magnetotail

AU - Borovsky, Joseph E.

AU - Denton, Michael H.

N1 - ©2012. American Geophysical Union. All Rights Reserved.

PY - 2011/12/28

Y1 - 2011/12/28

N2 - 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.

AB - 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.

KW - VAN-ALLEN RADIATION

KW - SOLAR-WIND STREAMS

KW - WAVE-PARTICLE INTERACTIONS

KW - SUPERDENSE PLASMA SHEET

KW - RELATIVISTIC ELECTRONS

KW - GEOSYNCHRONOUS ORBIT

KW - MAGNETIC STORM

KW - GEOMAGNETIC-FIELD

KW - INNER MAGNETOSPHERE

KW - GEOSPACE INTERACTIONS

U2 - 10.1029/2011JA016713

DO - 10.1029/2011JA016713

M3 - Journal article

VL - 116

SP - -

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

M1 - A12228

ER -