First Results from the Source/loss-cone Energetic Particle Spectrometer
(SEPS) on the NASA POLAR Satellite
R. Davis, K. Moser, A. White, and H.D. Voss
Taylor University, 500 W. Reade Ave., Upland, IN 46989-1001
We present new high angular resolution (+/- 1.5°) energetic particle images of the
source and loss cone in six two-dimensional cameras, each using 128 detectors (pixels).
The loss cone is produced in the earth's radiation belt because energetic charged
particles collide with the atmosphere when their velocity is quasi-parallel to the
magnetic field vector. The SEPS instrument is loacted on the despun platform of the NASA
POLAR satellite. POLAR was launched into a 9 Re apogee orbit in February, 1996. The
platform is usually programmed to point for L<6 in the vicinity of the loss cone. The
SEPS images provide the first measurements of the distribution function of particles at
high altitudes. By mapping the loss and source cone in detail a better understanding is
obtained of diffusion mechanisms, wave particle interactions, and direct precipitation
when compared with data from the other POLAR instruments. Currently we are evaluating the
performance of this new type of instrument and in particular the physics related to
relativistic electrons at the Trapping Boundary.
This page was last updated on January 22, 1997
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