Ionospheric footprint of magnetosheathlike particle precipitation observed by an incoherent scatter radar
- Geoscience and Engineering Center, Menlo Park, CA (United States)
- John Hopkins Univ., Laurel, MD (United States)
- Phillips Lab., Hanscom Air Force Base, Bedford, MA (United States)
The authors have examined Sondrestrom incoherent scatter radar observations of ionospheric plasma density and temperature distributions and measurements of F region ion drifts that were made during a prenoon pass of the DMSP-F7 satellite through the radar field of view. The spacecraft traversed a region of intense electron precipitation with a characteristic energy below approximately 200 eV. Particles with such low characteristics energies are believed to be directly or indirectly of magnetosheath origin. The precipitation region had a width of about 2{degrees} invariant latitude and covered the low-latitude boundary layer (LLBL), the cusp, and the equatorward section of the plasma mantle (PM). The corotating radar observed a patch of enhanced electron density and elevated electron temperature in the F2 region between about 10.5 and 12 magnetic local time in the same invariant latitude range where DMSP-F7 detected the soft-electron flux. The ion drift pattern, also obtained by radar, shows that it is unlikely that the plasma patch was produced by solar radiation and advected into the radar field of view. The authors suggest that the radar observed modifications of the ionospheric plasma distribution, which resulted from direct entry of magnetosheath electrons into the magnetosphere and down to ionospheric altitudes. Model calculations of the ionospheric response to the observed electron precipitation support their interpretation. The spectral characteristics of the electron flux in the LLBL, cusp, and equatorward section of the PM were in the case too similar to allow to distinguish between them by using incoherent scatter radar measurements only. 39 refs., 7 figs., 1 tab.
- OSTI ID:
- 29004
- Journal Information:
- Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Journal Issue: A3 Vol. 99; ISSN JGREA2; ISSN 0148-0227
- Country of Publication:
- United States
- Language:
- English
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