New Type of Short High‐Frequency VLF Patches (“VLF Birds”) Above 4–5 kHz
نویسندگان
چکیده
Abstract The new type of daytime natural very low frequency (VLF) whistler mode emissions the magnetospheric origin was found in VLF observations at Kannuslehto station ( L ∼ 5.5) Northern Finland. events occurred frequencies above 4–5 kHz even up to 15 kHz. These have never been observed earlier spectrograms because they were hidden by strong impulsive atmospherics (sferics) same range originating lightning discharges. After filtering out sferics, we surprisingly discovered completely types high right‐hand polarized peculiar with various unusual dynamic spectra. typically occur as a sequence number short (∼1–3 min) burst‐like structures or single patches total duration few hours. spectral peculiarities several long‐lasting well individual are discussed. spectra these raise question temporal and spatial details wave‐particle interactions plasma. only under quiet weakly disturbed space weather conditions, but during small negative values Dst index, indicating presence certain excess radiation belt electrons. Note, much higher than half equatorial electron gyrofrequency which is equal ∼2.7 5.5. It seems that generated deep magnetosphere, detailed nature, generation region, propagation behavior newly remain unknown. An appearance could be an indirect indicator local enhancement fluxes not directly measured may absence visible ground‐based geomagnetic disturbances. Further researches shed light on occurring Earth's belts.
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ژورنال
عنوان ژورنال: Journal Of Geophysical Research: Space Physics
سال: 2021
ISSN: ['2169-9402', '2169-9380']
DOI: https://doi.org/10.1029/2020ja028601