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Plasmapause undulation of 17 April 2002
Author(s) -
Goldstein J.,
Sandel B. R.,
Hairston M. R.,
Mende S. B.
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 - 10.1029/2004gl019959
Subject(s) - plasmasphere , substorm , geology , equator , geophysics , ionosphere , azimuth , polarization (electrochemistry) , altitude (triangle) , latitude , physics , geodesy , magnetosphere , plasma , astronomy , chemistry , geometry , mathematics , quantum mechanics
We report IMAGE EUV observations of a striking undulatory motion of the plasmapause that occurred on 17 April 2002, in which a large ripple propagated westward across the duskside plasmapause. From the plasmapause motion we infer a peak E‐field of ≈3 mV/m associated with the undulation, and estimate the undulation's equatorial azimuthal speed to be 0.9 rad/hr ≈ 4 R E /hr, corresponding to ≈1 km/s in the ionosphere (using an R 3/2 dependence to map from the equator). Because DMSP ion drift data at 850 km altitude show the presence of a subauroral polarization stream (SAPS) flow channel ≈1 km/s at the same location and time as the undulation, we assert that SAPS was responsible for removal of plasma during the undulation. The SAPS apparently formed in response to a 19:00 UT substorm onset.