Field‐aligned electron flux oscillations that produce flickering aurora

Abstract

Measurements of energetic electrons that produce flickering aurora were made by a pair of sounding rockets launched during a slowly evolving auroral breakup. Both payloads passed through a broad inverted‐V structure. A component of the electron distribution function was closely aligned with the magnetic field over a broad energy range that extended from low energies up to the inverted‐V differential energy flux peak. High time resolution measurements of the field‐aligned component showed the presence of order of magnitude coherent flux oscillations. Source altitudes between 4000 and 8000 km were derived from velocity dispersion of the flux oscillations. A ground‐based TV camera recorded visual flickering in the vicinity of the payloads' auroral footprints during periods when flux oscillations were present. Measurements are compared with previous observations of electron flux oscillations, and possible sources for the field‐aligned component are discussed.