| Pulsating aurora is defined as individually pulsating patches of light within diffuse aurora. Using a high-speed photomultiplier and extremely low frequency (ELF) wave receiver, several events of pulsating aurora were observed during two separate campaigns in 2002 and 2003. Some correlation is found between the data and theories of pulsation generation mechanisms (namely the flow cyclotron maser, the bounce drift resonance and the field line resonance). Observations include examples of simultaneous oscillations at two distinct frequencies, two examples of frequency increase, and several examples of spike-like behavior. These last two observations are consistent with the theory of the flow cyclotron maser. In highest frequency event studied, we also observed ELF waves at the same frequency as observed in the optical data, which we believe to be the first direct observation of pulsation-causing waves. |
