Simultaneous Observations of ELF/VLF Rising‐Tone Quasiperiodic Waves and Energetic Electron Precipitations in the High‐Latitude Upper Ionosphere. Issue 5 (25th May 2020)

• Record Type: Journal Article
• Authors: Zhima, Zeren; Huang, Jianping; Shen, Xuhui; Xia, Zhiyang; Chen, Lunjin; Piersanti, Mirko; Yang, Yanyan; Wang, Qiao; Zeng, Li; Lei, Jungang; Chu, Wei; Yan, Rui; Zhao, Shufan; Hu, Yunpeng; Guo, Feng
• Is Part Of: Journal of geophysical research. Volume 125:Issue 5(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-05-25
• Subjects: high latitude -- ionosphere -- quasiperiodic waves -- energetic electron -- generation mechanism -- ULF wave; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2019JA027574
• Languages: English
• ISSNs: 2169-9380

Abstract

Key Points: The rising‐tone quasiperiodic waves with simultaneous energetic precipitations were observed in the dayside ionosphere The wave spectral properties show dynamic structures with clear cutoff frequencies The quasiperiodic modulations are probably related to ULF waves or the wave particle cyclotron instability Abstract: The quasiperiodic (QP) waves accompanied by simultaneous energetic electron precipitations in the high‐latitude ionosphere were recorded by the sun‐synchronous circular orbit China Seismo‐Electromagnetic Satellite (CSES). The new features of QP waves observed by CSES are the well‐pronounced rising‐tone structures and very short repetition periods, which are not ofen reported by previous studies. The repetition period of QP waves varies from ~1 to over 20 s, with wave spectral properties displaying dynamic structures and clear cutoff frequencies. The majority of QP waves appear at geomagnetic latitudes from ~50° to 65°, and L shell from ~3.5 to 4, mostly inside the plasmapause. The QP waves obliquely propagate towards decreasing L shell directions with right‐handed polarization, with wave normal angles varying from ~30° to 50°. Out of the 68 events examined, 19 of them show synchronous variations of ultralow frequency (ULF) magnetic field pulsations in certain portions of the wave event. The energetic electrons predominately precipitate in a double‐peak pattern (~400 to 550 keV and ~700 to 800 keV). No clear periodic precipitating fluxes were found. The estimated time interval of energetic electrons driving free energy to modulate the whistler‐mode waves varies from 0.04 to 30°s, which is roughly consistent with the observed repetition periods (10 to over 20 s). For the fast repetition period (~1 to 2s) QP wave, it is likely caused by the bouncing of the extremely/very low frequency (ELF/VLF) whistler‐mode wave packets from the conjugate ionosphere.