Suprathermal particle observations in the nighttime ionosphere at low latitudes

A rocket borne electrostatic analyzer was flown through the near equatorial ionosphere, up to L ∼ 1.3, at night, during a magnetic storm associated with spread‐F. After careful correction of the observed signal, which was highly contaminated by the U.V. night glow, it appears a field aligned, upwards directed flux of soft ions with a power law spectrum, through a restricted altitude range. A comparison with earlier results indicates that it is not inconsistent with previously published upper limits, owing to the limited spatial extent of the phenomenon.