Premium
Low energy upflowing ion events observed by EXOS‐D: Initial results
Author(s) -
Sagawa E.,
Iwamoto I.,
Watanabe S.,
Whalen B. A.,
Yau A. W.,
Fukunishi H.
Publication year - 1991
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/91gl00028
Subject(s) - physics , ion , atomic physics , flux (metallurgy) , conical surface , pitch angle , magnetic field , field (mathematics) , computational physics , geophysics , materials science , mathematics , quantum mechanics , pure mathematics , metallurgy , composite material
Initial observations of low‐energy upflowing ion events from the Suprathermal Ion Mass Spectrometer (SMS) on EXOS‐D are presented. The SMS instrument on EXOS‐D measures the mass composition, energy and angular distributions of thermal and suprathermal ions in the 0.1–4000 eV/q energy‐per‐charge and 0.8–70 amu/q mass‐per‐charge ranges. Two events are examined. The first features predominantly conical ion pitch‐angle distributions and the second has mainly field‐aligned distributions. Both events displayed small scale variations in upward flux, composition, and angular characteristics, and coincided with small‐scale magnetic field fluctuations. In both events, the peak He + and H + fluxes were comparable; the O + flux was a factor of 5–10 larger. The pitch‐angle distribution often switched rapidly between field‐aligned and conical.