Balloon observations of auroral zone X rays in conjugate regions: 2. Microbursts and pulsations

Abstract

Simultaneous balloon observations of X-ray pulsations in the 5–10 second range made from Fairbanks, Alaska, and Macquarie Island, Australia, showed no detailed correlation in time or amplitude. Observations in the northern hemisphere, with two balloon instruments separated by about 150 km in the east-west direction, showed no obvious correlation, but when the separation was reduced to about 100 km in the north-south direction, X-ray pulsations showed in-phase variations. Observations with two balloon instruments separated by 150 km in the east-west direction showed time coincidences for about one-third of the microbursts; the other two-thirds were observed on one balloon or the other. From the small scale size of microburst electron precipitation it is suggested that magnetospheric plasma instabilities are responsible for the electron bombardment of the auroral zone atmosphere. Similar considerations are suggested for pulsating electron precipitation.