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Electric fields deduced from plasmapause motion in IMAGE EUV images
Author(s) -
Goldstein J.,
Wolf R. A.,
Sandel B. R.,
Reiff P. H.
Publication year - 2004
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 - 10.1029/2003gl018797
Subject(s) - plasmasphere , electric field , physics , geophysics , whistler , extreme ultraviolet , astrophysics , plasma , magnetosphere , optics , laser , quantum mechanics
The IMAGE extreme ultraviolet (EUV) imager obtained global images of the plasmasphere erosion of 10 July 2000, in which the nightside plasmapause moved inward by about 2 R E during 5–8 UT. We use plasmapause motion to infer the electric (E) field component tangent to the moving plasmapause; in general we lack knowledge of the perpendicular E‐field component. In the midnight‐to‐dawn quadrant where the plasmapause shape is very nearly circular, the tangential E‐field component is equal to the azimuthal electric field E φ . Peak westward E‐fields of 0.6–1.3 mV/m were found at the plasmapause between L ≈ 4–6, an inner magnetospheric E‐field that was 25% of the solar wind E‐field. The MLT‐concentration of the inferred E‐field suggests that convective flows may produce partial indentation of the nightside plasmapause (especially in the midnight‐to‐dawn sector) that widens as the edges of the indentation propagate azimuthally.