First magnetospheric echo traces from the Radio Plasma Imager on IMAGE


B. W. Reinisch(1), D. M.Haines(1), I. A. Galkin(1), X. Huang(1),
  G. Sales(1), J. L. Green(2), R. F. Benson(2), S. F. Fung(2),
  W. W. L. Taylor(3), J.-L. Bougeret(4), R. Manning(4),
  P. H. Reiff(5), D. L. Carpenter(6) and D. L. Gallagher(7)

1 Center for Atmospheric Research, University of Massachusetts, Lowell, MA 
2 NASA Goddard Space Flight Center, Greenbelt, MD 
3 Raytheon ITSS Corporation, Lanham, MD 
4 Observatoire de Paris, Meudon, France
5 Rice University, Houston, TX 
6 STAR Laboratory, Stanford University, Palo Alto, CA 
7 NASA Marshall Space Flight Center, Huntsville, AL

Abstract

The radio plasma imager (RPI) on the IMAGE satellite is a low-frequency
radar system that uses orthogonal 500-m tip-to-tip dipoles to transmit
RF pulses with frequencies from 3 kHz to 3 MHz. A third 20-m tip-to-tip
dipole antenna along the spin axis is used for reception together with
the two long antennas providing direction of arrival capability.  The
minimum pulse length of 3.2 ms yields a range resolution of 480 km.
When the spacecraft is in the magnetospheric cavity (altitude of 5-7 RE)
RPI can receive echoes associated with the plasmasphere, the magnetopause
and the cusp region, at frequencies between ~10 and 100 kHz. At high
altitudes, higher frequency echoes are found reflecting from the
topside ionosphere. This paper will present some of the first echo
observations measured by the RPI instrument.

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Submitted to the proceedings of the Ukrastro-2000 Conference
November, 2000