The Solar, Anomalous, and Magnetospheric Particle Explorer

The Solar, Anomalous, and Magnetospheric Particle Explorer, SAMPEX, will carry out energetic particle studies of outstanding scientific questions in the fields of space plasma physics, solar physics, magnetospheric and middle atmospheric physics, and cosmic ray physics. SAMPEX will measure the electron and ion composition of energetic parti~le populations from -0.4 Me V /nucleon to hundreds of MeV /nucleon from a zenith-pointing small satellite in near-polar orbit, using a coordinated set of detectors with excellent charge and mass resolution, and with higher sensitivity than previously flown instruments. While over the magnetic poles, the instruments will study t~e composition of anomalous cosmic rays, solar energetic particles, and galactic cosmic rays. At lower magnetic latitudes, geomagnetic cutoff effects will allow determination of the ionization state of these particles at energies much higher than can be studied from interplanetary spacecraft. At subauroral latitudes, SAMPEX wiJI also observe precipitating relativistic magnetospheric electrons, which undergo important interactions within the middle atmosphere.