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The ionospheric signature of Pi 2 pulsations observed by STARE

Journal Article · · Journal of Geophysical Research; (United States)
DOI:https://doi.org/10.1029/92JA00440· OSTI ID:7158450
 [1];  [2]
  1. CSIR, Hermanus (South Africa)
  2. Max-Planck-Inst. fuer Aeronomie, Katlenburg-Lindau (Germany)
This study extends the work of Sutcliffe and Nielsen (1990) in which a classical Pi 2 pulsation was first isolated in Scandinavian Twin Auroral Radar Experiment (STARE) data. A high-pass-filtering technique is used to remove the background electric field in the STARE data and so reveal the spatial and temporal ionospheric signatures of the Pi 2 pulsation electric fields. A number of events are identified and examples presented in which pulsation electric fields up to 50 mV/m are observed. Magnetic field oscillations computed from the filtered STARE data using the Biot-Savart law correlate well with pulsation magnetometer data. A 180 {degree} phase difference is observed between high- and low-altitude X component pulsations. The ionospheric signature of a Pi 2 is located slightly poleward of the core of the auroral breakup region where the southward, westward, and northward directed background electric fields coverage; the strongest pulsation fields occur in the region of equatorward directed electric fields. The ionospheric electric field patterns of the Pi 2 pulsations determined from the STARE data correlate well with those modeled for a transverse Alfven wave incident on an east-west aligned high-conductivity strip in the ionosphere.
OSTI ID:
7158450
Journal Information:
Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 97:A7; ISSN JGREA; ISSN 0148-0227
Country of Publication:
United States
Language:
English