Application of ionospheric topside-sounding results to magnetospheric physics 
and astrophysics

Robert F. Benson and Vladimir A. Osherovich


A brief review is presented to illustrate how the knowledge and experience
gained from investigations of ionospheric topside-sounder ionograms has
benefited scientific research beyond the ionosphere. In particular, to the
interpretation of (1) natural radio emissions from space plasmas, (2)
sounder-stimulated echoes and plasma emissions, and plasma diagnostics in
planetary magnetospheres and (3) X-ray spectra of disks around neutron stars and
black holes. The relevant data are from 60 satellite years of ionospheric
topside-sounder operations by the four satellites of the International
Satellites for Ionospheric Studies (ISIS) program from 1963 through 1989. Not
all of these data were reduced to ionograms on 35-mm film. An ongoing effort at
the NASA Goddard Space Flight Center is producing digital topside-sounder
ionograms directly from a selected subset of the original telemetry tapes. More
than 300,000 digital ionograms are now in the National Space Science Data Center
at the NASA GSFC ( http://nssdc.gsfc.nasa.gov/space/isis/isis-status.html).

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Radio Science, 39, RS1S28, doi:10.1029/2002RS002834, 2004