Remote Detection of Drift Resonance Between Energetic Electrons and Ultralow Frequency Waves: Multisatellite Coordinated Observation by Arase and Van Allen Probes. Issue 21 (5th November 2019)

• Record Type: Journal Article
• Authors: Teramoto, M.; Hori, T.; Saito, S.; Miyoshi, Y.; Kurita, S.; Higashio, N.; Matsuoka, A.; Kasahara, Y.; Kasaba, Y.; Takashima, T.; Nomura, R.; Nosé, M.; Fujimoto, A.; Tanaka, Y.‐M.; Shoji, M.; Tsugawa, Y.; Shinohara, M.; Shinohara, I.; Blake, J. B.; Fennell, J.F.; Claudepierre, S.G.; Turner, D. L.; Kletzing, C. A.; Sormakov, D.; Troshichev, O.
• Is Part Of: Geophysical research letters. Volume 46:Issue 21(2019)
• Page Start: 11642
• Page End: 11651
• Publication Date: 2019-11-05
• Subjects: Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2019GL084379
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: We report the electron flux modulations without corresponding magnetic fluctuations from unique multipoint satellite observations of the Arase (Exploration of Energization and Radiation in Geospace) and the Van Allen Probe (Radiation Belt Storm Probe [RBSP])‐B satellites. On 30 March 2017, both Arase and RBSP‐B observed periodic fluctuations in the relativistic electron flux with energies ranging from 500 keV to 2 MeV when they were located near the magnetic equator in the morning and dusk local time sectors, respectively. Arase did not observe Pc5 pulsations, while they were observed by RBSP‐B. The clear dispersion signature of the relativistic electron fluctuations observed by Arase indicates that the source region is limited to the postnoon to the dusk sector. This is confirmed by RBSP‐B and ground‐magnetometer observations, where Pc5 pulsations are observed to drift‐resonate with relativistic electrons on the duskside. Thus, Arase observed the drift‐resonance signatures "remotely, " whereas RBSP‐B observed them "locally." Plain Language Summary: Magnetohydrodynamic waves in the outer radiation belt with periods of ~150–250 s occasionally cause the acceleration of energetic electrons drifting eastward around the Earth. We examined the longitudinal distributions of the interaction region in which magnetohydrodynamic waves with periods of ~150–250 s interacted with energetic electrons on 30 March 2017, using simultaneously observed data by multisatellite observations from the Arase and the Radiation Belt Storm Probe (RBSP)‐B satellites. Both satellites observed radiation belts at different local times but at almost the same Earth radii. The Arase satellite located in the dawn sector observed energetic electron flux modulations that had clear energy dispersion signatures, while magnetohydrodynamic waves with the same period were not identified. However, the RBSP‐B located in the dusk sector simultaneously observed magnetohydrodynamic waves and the energetic electron modulations with the characteristics of the interaction. This multipoint measurement indicates that the interaction region is limited from the postnoon to the dusk sector. Key Points: Arase observed flux modulations of relativistic electrons at 04 MLT without variations in the ambient magnetic and electric fields Time‐of‐flight analysis from the energy dispersion of relativistic electrons identified the drift‐resonant region to be 14–18 MLT The interactions between Pc5 waves and relativistic electrons occurred at a limited local time even though the estimated m number is small