Tracking the Region of High Correlation Between Pulsating Aurora and Chorus: Simultaneous Observations With Arase Satellite and Ground‐Based All‐Sky Imager in Russia

• Published in: Journal of geophysical research. Space physics 2019-04, Vol.124 (4), p.2769-2778
• Main Authors: Kawamura, S., Hosokawa, K., Kurita, S., Oyama, S., Miyoshi, Y., Kasahara, Y., Ozaki, M., Matsuda, S., Matsuoka, A., Kozelov, B., Kawamura, Y., Shinohara, I.
• Format: Article
• Language: English
• Subjects: Auroral substorms; Blinking; Chorus wave; Chorus waves; Correlation coefficient; Correlation coefficients; Electromagnetic radiation; Electron precipitation; Electrons; Field of view; Luminosity; Magnetospheres; Particle interactions; Periodicities; Pulsating Aurora; Satellite observation; Satellites; Waves
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1029/2019JA026496

The temporal modulations of magnetospheric chorus waves are one of the candidates for explaining quasiperiodic precipitation of energetic electrons causing pulsating aurora (PsA). To confirm fully the direct association between PsA and chorus, an extended interval of PsA (~1 hr) simultaneously observed by the Arase satellite and a ground‐based all‐sky imager in Apatity, Kola Peninsula, Russia was examined. In particular, a region of high correlation between PsA and chorus was continuously tracked within the field of view of the all‐sky imager. The result showed that the high‐correlation region and the modeled footprint of Arase moved in tandem. This strongly implies that the chorus and PsA electrons originated from the same local interaction region. In addition, the location of the high‐correlation region showed sudden jumps, which were probably associated with the motion of the satellite through discrete spatial structures of plasma in the region of wave‐particle interaction. Plain Language Summary Pulsating aurora (PsA), which consists of luminous patches/arcs blinking with various periodicities ranging from a few to a few tens of seconds, is known to occur very frequently during the recovery phase of auroral substorms. It has been suggested that the luminosity variation of PsA is controlled by natural electromagnetic waves in space, which are called chorus waves. There have been several studies that demonstrated one‐to‐one correspondence between the temporal variations of PsA and chorus waves. However, it is still unclear how long such a good correlation between PsA and chorus is preserved. In this study, an extended interval of PsA (~1 hr) simultaneously observed by a newly launched magnetospheric satellite, Arase, and a ground‐based high‐speed all‐sky imager in Apatity, Kola Peninsula, Russia was investigated. As a result, not only was the correspondence between PsA and chorus verified but also the motion of the high‐correlation region (correlation coefficient > 0.5) was successfully tracked in a continuous manner. The obtained long‐lasting reasonable correlation proves that the chorus waves control the luminosity variation of PsA. In addition, the region of high correlation between PsA and chorus showed sudden jumps, which could be caused by the motion or variation of the fine‐scale structure of the wave‐particle interaction region in space. Key Points Observation of the Arase satellite with an all‐sky imager revealed a long‐lasting correlation betwe