Properties of auroral radio absorption patches observed in the morning sector using imaging riometer and incoherent-scatter radar

The investigation concerns the size and motion of spatial fine structure in auroral radio absorption as observed by imaging riometer. Electron density profiles in the D and E regions determined by simultaneous incoherent-scatter radar were inverted to provide an estimate of the energy spectrum of the incoming electrons, and it is shown that the gradient-curvature drift at these energies is not consistent with the observed motion of the absorption fine structure, being too large by a factor of 5 or 6. However, a comparison with F-region drifts determined by the SuperDARN radar network supports a hypothesis that the cause lies in moving structures within the magnetosphere.