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.

A class of pulsating aurora has been observed in which the repeated spatial expansion of a patch from a small persistent core region is evidently dependent on the attainment of a critical intensity level in this core region. Characteristics of patches exhibiting this behavior are summarized and the phenomenon is discussed in relation to possible triggered instabilities of the precipitating electron beam.

Using a technique that enables one to digitize the brightness of auroral displays from individual fields of a video signal, we have analyzed the frequency content of flickering aurora. Through the application of Fourier analysis to our data, we have found that flickering aurora contains a wide range of enhanced frequencies, although the dominant frequency enhancement generally occurs in the range 6–12 Hz. Each incidence of flickering that we observed was associated with increased radio wave absorption. Furthermore, we have found that flickering occurs in bright auroral surges, the occurrence of which is not limited to the ‘breakup’ phase of auroral substorms. Our results are interpreted in terms of a recently proposed theory of fluctuating double layers that accounts for a number of the observational features.

An Image Intensifier-TV system was operated in a double imaging mode to record simultaneously the auroral emissions at k3914 and k5577. Cross-spectral analysis of thirty-nine 3-min periods yielded a mean lifetime for the O(1S) state of oxygen ranging from 0.59 to 0.3 sec. The significance of these results in relation to possible mechanisms, quenching coefficients, and auroral heights is discussed.

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