magnetosphere. EA consists of two nested sets of quadrispherical electrostatic
analyzers. The inner analyzer measures electrons in the energy range from 6--36
eV, and the outer one measures positive ions from 7 eV/Q to 42 keV/Q. The field
of view for each quadrispherical analyzer covers 10 degrees by 145 degrees,
where the longer dimension is parallel to the satellite spin axis.

LEP-SW measures three-dimensional velocity distributions of solar wind ions in
the energy range from 0.1--8 keV/Q with a 270 degree spherical electrostatic
analyzer with a field of view of 5 degrees by 60 degrees.

LEP-MS is an energetic ion mass spectrometer, which provides three-dimensional
determinations of the ion composition in 32 steps over the energy range of
0--25 keV/Q. All sensors operate continuously as long as the spacecraft power
budget can allow, except for the orbit/attitude maneuvering operation.

When spacecraft power budget is not sufficient to fully operate the
instruments, priority is given to LEP-EA and LEP-E.

Although this experiment ceased operation shortly after launch, the LEP-EA and
LEP-SW portions of the experiment resumed operation in late 1993 and have
worked well ever since.

Principal Investigator:
Dr. Tsugunobu Nagai
Tokyo Institue of Technology
Earth and Planetary Sciences
Tokyo 152-8551 Japan
Phone:
Fax:
e-mail: nagai@geo.titech.ac.jp

See:
http://pwg.gsfc.nasa.gov/geotail_inst.shtml