A proposed production model of rapid subauroral ion drifts and their relationship to substorm evolution

Тип публикации: статья из журнала

Год издания: 1993

Идентификатор DOI: 10.1029/92JA01975

Ключевые слова: 71 CLASSICAL AND QUANTUM MECHANICS, general physics, Ion drift, correlations, coupling, ionosphere, electric conductivity, magnetic storms, Auroral oval, E region, electric fields, Electron precipitation, F region, Magnetic bays, Plasma drift, CHARGED-PARTICLE PRECIPITATION, Earth atmosphere, electrical properties, physical properties, Planetary ionospheres

Аннотация: The authors conduct a study of subauroral ion drifts (SAID), to examine their correlation with magnetic storms. By a SAID one means a latitudinally narrow band of westward drifting ions located on the equatorial side of the auroral oval in the evening ionosphere. They look at the relationship of SAID to various stages in the development of a substorm. Data comes from DE 1, which provided auroral images, DE 2 which measured ionospheric parameters by means of magnetometers, an ion drift meter, a low altitude plasma instrument, and a retarding potential analyzer, and measurements of particle injection made by instruments at geosynchronous orbit. Analysis of the data showed very low ion drifts or field aligned currents in regions equatorward of the auroral oval before or after substorms. After substorm onset ion drifts and field aligned currents were observed extending well equatorward of the oval. There was no clear drift spike in these observations suggesting a SAID. They never saw a SAID occuring within 30 minutes of substorm onset. In almost all observations of a SAID which could be correlated with the recovery phase of the substorm, the SAID was initiated in the recovery phase. The authors then propose a model to explain the SAID which draws upon a decrease in the conductivity in the E and F regions between the band of electron precipitation in the oval and the equatorward band of ion precipitation. Several factors play into this decrease, but its occurance allows the growth of large electric fields which can drive the plasma drift as the equatorward extent of the substorm expansion shrinks in the recovery phase.

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Издание

Журнал: Journal of Geophysical Research

Выпуск журнала: Т.98, 4

Номера страниц: 6069-6078

ISSN журнала: 01480227

Издатель: William Byrd Press for John Hopkins Press

Авторы

  • Anderson P.
  • Hanson W.B.
  • Heelis R.A.
  • Craven J.D.
  • Baker D.N.
  • Frank L.A. (Siberian Federal University)

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