Pulsating aurora associated with temporal structures of chorus elements: Coordinated Arase satellite and PWING observations

It is commonly believed that luminosity variations of pulsating aurora are characterized by temporal structures of chorus waves (e.g., duration of wave bundle and each element spacing). Theoretical and simulation studies support this idea, and also suggest that faster luminosity variations at tens of Hz can be present. This is because that discrete chorus element consists of amplitude modulations with a few tens of milliseconds referred to as subpacket structures. However, the detailed temporal characteristics between chorus elements and pulsating auroras less than 1 s are still poorly understood. Here we report conjugate observations of pulsating aurora by the Arase satellite and ground-based high-speed (100 Hz) camera at Gakona, Alaska, which is one ground site of the ground-based PWING network. The Arase satellite observed chorus waveforms in situ in the magnetosphere while the ground-based camera detected pulsating aurora events. The observed pulsating aurora showed similar temporal characteristics with not only each chorus element spacing, but also chorus amplitude modulations of tens of milliseconds. This observation result suggests that subpacket structures of a chorus element can cause a rapid pitch angle scattering of energetic electrons. In this presentation, we will report detailed conjugate observation results of pulsating aurora by the Arase satellite and the ground-based PWING network.