NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Collections About News Help Login
Back to Results
Extremely Low Ionospheric Peak Altitudes in the Polar-Hole RegionVertical electron-density (N (sub e)) profiles, deduced from newly-available ISIS-II digital ionospheric topside-sounder data, are used to investigate the "polar-hole" region within the winter, nighttime polar cap ionosphere during solar minimum. The hole region is located around 0200 MLT near the poleward side of the auroral oval. Earlier investigations had revealed very low N (sub e) values in this region (down to 200/cu cm near 300 km). In the present study, such low N, values (approx. 100/cu cm) were only found near the ISIS (International Satellite for Ionospheric Study)-II altitude of 1400 km. The peak ionospheric concentration below the spacecraft remained fairly constant (approx. 10 (exp 5)/cu cm across the hole region but the altitude of the peak dropped dramatically. This peak dropped, surprisingly, to the vicinity of 100 km. These observations suggest that the earlier satellite in situ measurements, interpreted as deep holes in the ionospheric F-region concentration, could have been made during conditions of an extreme decrease in the altitude of the ionospheric N (sub e) peak. The observations, in combination with other data, indicate that the absence of an F-layer peak may be a frequent occurrence at high latitudes.
Document ID
20000023161
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Benson, Robert F. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Grebowsky, Joseph M. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
September 7, 2013
Publication Date
January 1, 1999
Subject Category
Geophysics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Related Records

There are no records associated with this record.
No Preview Available