Microburst phenomena: 2. Auroral‐zone electrons

Observations made during a high time resolution mode of operation of the Injun 3 satellite have identified electrons comprising auroral‐zone microbursts, the parent phenomenon of the microburst X‐ray fluxes observed by balloon‐borne instruments. These electron bursts, detected in the E e ≥ 40 kev (180°) (precipitating) detector and less frequently in the E e ≥ 40 kev (90°) (trapped) detector, have time profiles whose detailed character is similar to those of the daughter bremsstrahlung X‐ray bursts and exhibit typical peak fluxes of J 0 ( E e ≥ 40 kev) ∼ 3 × 10 5 electrons cm −2 sec −1 ster −1 in the 180° detector. Statistical studies of data from the entire satellite lifetime reveal microburst occurrence predominantly in the regions of 6 ≤ L ≤ 8.5 and 4:30 ≤ magnetic local time ≤ 12:30. Detailed statistical distributions of microburst occurrence as functions of local time and L are presented.