Storm time evolution of the outer radiation belt: Transport and losses

A. Y. Ukhorskiy, B. J. Anderson, P. C. Brandt, N. A. Tsyganenko

Результат исследований: Научные публикации в периодических изданияхстатья

122 Цитирования (Scopus)

Аннотация

During geomagnetic storms the magnetic field of the inner magnetosphere exhibits large-scale variations over timescales from minutes to days. Being mainly controlled by the magnetic field the motion of relativistic electrons of the outer radiation belt can be highly susceptible to its variations. This paper investigates evolution of the outer belt during the 7 September 2002 storm. Evolution of electron phase space density is calculated with the use of a test-particle simulation in storm time magnetic and electric fields. The results show that storm time intensification of the ring current produces a large impact on the belt. In contrast to the conventional Dst effect the dominant effects are onadiabatic and lead to profound and irreversible transformations of the belt. The diamagnetic influence of the partial ring current leads to expansion of electron drift orbits such that their paths intersect the magnetopause leading to rapid electron losses. About 2.5 hr after the storm onset most of the electrons outside L = 5 are lost. The partial ring current pressure also leads to an electron trap in the dayside magnetosphere where electrons stay on closed dayside drift orbits for as long as 11 hours. These sequestered electrons are reinjected into the outer belt due to partial recovery of the ring current. The third adiabatic invariant of these electrons exhibits rapid jumps and changes sign. These jumps produce localized peaks in the L*-profile of electron phase space density which have previously been considered as an observable indication of local electron acceleration.
Язык оригиналаанглийский
Номер статьиA11S03
Число страниц9
ЖурналJOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
Том111
Номер выпускаA11S03
DOI
СостояниеОпубликовано - 1 ноя 2006

Предметные области Scopus

  • Физика и астрономия (все)

Ключевые слова

  • Geomagnetic storm
  • radiation belt
  • radiation belt electrons
  • magnetosphere

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