Wind observations of suprathermal electrons in the interplanetary medium

Abstract

We review some of the new results for suprathermal electrons obtained with the 3-D Plasma and Energetic Particle Instrument on the WIND spacecraft, which provides high sensitivity electron and ion measurements from solar wind thermal plasma up to ≳MeV energies. These results include: (1) the observation of solar impulsive electron events extending down to ∼0.5 keV energy; (2) the observation of a turnover at ∼12 keV for electrons in a gradual large solar energetic particle (LSEP) event; (3) the detection of a quiet-time population (the 'superhalo') of electrons extending up to ∼100 keV energy; and (4) the probing of the magnetic topology and source region for magnetic clouds, using electrons. These unique WIND measurements are highly complementary to the particle composition measurements which will be made by ACE.