Energy spectral characteristics of auroral electron microburst precipitation

We consider data from a rocket experiment designed to study auroral microburst precipitation. Our rocket instruments had high energy spectral resolution which allowed us to characterize the electron energy spectra. Data from the field aligned electron detector show that the majority of the spectra fit an exponential form in the 45-70 keV energy range. Approximately 15% of the spectra fit a power law form for high energies (70-150 keV) and 45% fit an additional exponential form for low energies (20-45 keV). The multi-component spectra appeared during both microburst and non-burst times. The e-folding energies for the 45-70 keV energy range increased as the flux increased. Some of these features can be explained by a cyclotron wave-particle interaction mechanism. We also observed a weak peak in the energy spectrum at about 45 keV, suggesting the existence of field-aligned potential drops associated with microburst production.