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Influence of the equatorial irregularities and precipitations in the South Atlantic Magnetic Anomaly on the generation of auroral‐type plasma instabilities
Author(s) -
Prange Renée,
Bruston Paul
Publication year - 1980
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl007i008p00601
Subject(s) - ionosphere , geophysics , magnetosphere , physics , anomaly (physics) , plasma , magnetic field , south atlantic anomaly , geology , atmospheric sciences , computational physics , van allen radiation belt , condensed matter physics , quantum mechanics
Observational evidence of upward field‐aligned beams in the keV range has been obtained in the sub‐equatorial ionosphere above South America. These events can be related to coupled magnetic and ionospheric activity (magnetic storm, ionospheric irregularities). This result is in opposition with the current theory of the low‐latitude ionosphere. Its interpretation must assume that conditions exist for the growth of plasma instabilities. This implies a low plasma density, a close coupling between the ionosphere and the magnetosphere, and field‐aligned currents. Such suitable conditions have independently been observed in ionospheric irregularities (density, currents) or during magnetic storms (energetic particle precipitation) or they are deduced from the structure of the Anomaly (field‐aligned currents). This allows us to suggest that the South Atlantic Anomaly sometimes compares to the auroral oval and may develop some current‐driven plasma instabilities.