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Periodic Rising and Falling Tone ECH Waves From Van Allen Probes Observations
Author(s) -
Shen XiaoChen,
Li Wen,
Ma Qianli
Publication year - 2021
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl091330
Subject(s) - falling (accident) , physics , electron precipitation , van allen probes , earth's magnetic field , substorm , electron , atmospheric sciences , atomic physics , astrophysics , geophysics , van allen radiation belt , plasma , nuclear physics , magnetic field , magnetosphere , medicine , environmental health , quantum mechanics
Electron cyclotron harmonic (ECH) waves are known to precipitate plasma sheet electrons into the upper atmosphere and generate diffuse aurorae. In this study, we report quasiperiodic rising (3 events) and falling tone (22 events) ECH waves observed by Van Allen Probes and evaluate their properties. These rising and falling tone ECH waves prefer to occur during quiet geomagnetic conditions over the dusk to midnight sector in relatively high‐density (10–80 cm −3 ) regions. Their repetition periods increase with increasing L shell at L < 6, ranging from ∼60 to 110 s. The wave element duration varies from 10 to 130 s peaking at ∼40 s and the chirping rate peaks at ∼50 (∼−50) Hz/s for rising (falling) tones. Our findings reveal intriguing features of the ECH wave properties, which provide new insights into their generation and potential effects on electron precipitation.