Optical observations of flickering aurora and its spatiotemporal characteristics

Abstract

Flickering aurora is characterized by optical emissions varying in intensity with frequencies typically between 5 and 15 Hz. In this report we use high‐speed narrow field‐of‐view imaging in white light to determine the intensity variation and the apparent motion of the flickering spots. The characteristic patterns we find are compared with the spatial patterns derived from interference between electromagnetic ion‐cyclotron waves. It is found that good agreement is reached, which we argue should make a strong rejection criterion for theories of flickering aurora.