Electrostatic Electron Cyclotron Harmonic Waves as a Candidate to Cause Pulsating Auroras. Issue 23 (2nd December 2018)

• Record Type: Journal Article
• Authors: Fukizawa, M.; Sakanoi, T.; Miyoshi, Y.; Hosokawa, K.; Shiokawa, K.; Katoh, Y.; Kazama, Y.; Kumamoto, A.; Tsuchiya, F.; Miyashita, Y.; Tanaka, Y. ‐M.; Kasahara, Y.; Ozaki, M.; Matsuoka, A.; Matsuda, S.; Hikishima, M.; Oyama, S.; Ogawa, Y.; Kurita, S.; Fujii, R.
• Is Part Of: Geophysical research letters. Volume 45:Issue 23(2018)
• Page Start: 12, 661
• Page End: 12, 668
• Publication Date: 2018-12-02
• Subjects: pulsating aurora -- chorus -- electrostatic electron cyclotron harmonic -- Arase -- wave‐particle interaction -- inner magnetosphere; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2018GL080145
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Pulsating auroras (PsAs) are thought to be generated by precipitating electrons scattered by lower‐band chorus (LBC) waves near the magnetic equator. One‐to‐one correlation between the LBC intensity and the PsA intensity has been reported. Electrostatic electron cyclotron harmonic (ECH) waves can also scatter electrons. However, direct correlation between ECH and PsA has not been reported yet. In this study, using a coordinated Exploration of energization and Radiation in Geospace (Arase) satellite and ground‐based imager observation, we report that not only LBC but also ECH have correlation with PsA. We estimated the precipitating electron energy by assuming that the time lag when the cross‐correlation coefficient became the highest was travel time of electrons from the modulation region. We found that the estimated energies show reasonable values as the cyclotron resonance energy of each wave. Plain Language Summary: Pulsating auroras (PsAs), which have quasiperiodic on‐off switching emission, are caused by the intermittent electron precipitation from the magnetosphere. Such electrons are precipitated by wave‐particle interactions. The candidate waves to interact with electrons are lower‐band chorus (LBC) and electrostatic electron cyclotron harmonic (ECH) waves. One‐to‐one correspondence between the LBC wave intensity and the PsA intensity has been reported by previous studies. However, the correlation between ECH and PsA has not been reported yet. In this study, using a coordinated Exploration of energization and Radiation in Geospace (Arase) satellite and ground‐based all‐sky imager observation, we report that not only LBC but also ECH waves have correlation with PsAs. Key Points: The lower‐band chorus and electrostatic electron cyclotron harmonic wave intensities had correlation with the pulsating auroral intensity Taking advantage of high sampling rate of the imager, we estimated the energy of precipitating electrons The energy of precipitating electrons was reasonable compared with the cyclotron resonance energy of each wave