| definition |
- The Radio Plasma Imager (RPI) instrument on the IMAGE spacecraft is a low-power
radar which operates in the radio frequency bands which contain the plasma
resonance frequencies characteristic of the Earth's magnetophere (3 kHz to 3
MHz). RPI can locate regions of various plasma densities by observing radar
echos from the plasma that are reflected where the radio frequency is equal to
the plasma frequency. By stepping through various frequencies for the
transmitted signal, features of various plasma densities can be observed and,
by fitting contours and/or magnetospheric models to the features, a 3-D
specification of the shape of the magnetosphere can be created.
The RPI instrument consists of an electronics enclosure, four 250 m wire
antennae with deployers (including switches and couplers), and a z-axis boom
canister containing two 10 m lattice boom antennae and two preamplifiers.
For more information, see:
http://image.gsfc.nasa.gov/rpi/
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