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Whistler Influence on the Overall Very Low Frequency Wave Intensity in the Upper Ionosphere
Author(s) -
Záhlava J.,
Němec F.,
Pincon J. L.,
Santolík O.,
Kolmašová I.,
Parrot M.
Publication year - 2018
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2017ja025137
Subject(s) - whistler , ionosphere , physics , intensity (physics) , earth's magnetic field , geophysics , geomagnetic latitude , lightning (connector) , very low frequency , spacecraft , altitude (triangle) , computational physics , magnetic field , optics , astronomy , mathematics , power (physics) , quantum mechanics , geometry
We investigate the influence of lightning‐generated whistlers on the overall intensity of electromagnetic waves measured by the Detection of Electro‐Magnetic Emissions Transmitted from Earthquake Regions spacecraft (2004–2010, quasi Sun‐synchronous polar orbit with an altitude of about 700 km) at frequencies below 18 kHz. Whistler occurrence rate evaluated using an onboard neural network designed for automated whistler detection is used to distinguish periods of high and low whistler occurrence rates. It is shown that especially during the night and particularly in the frequency‐geomagnetic latitude intervals with a low average wave intensity, contribution of lightning‐generated whistlers to the overall wave intensity is significant. At frequencies below 1 kHz, where all six electromagnetic wave components were measured during specific intervals, the study is accompanied by analysis of wave propagation directions. When we limit the analysis only to fractional‐hop whistlers, which propagate away from the Earth, we find a reasonable agreement with results obtained from the whole data set. This also confirms the validity of the whistler occurrence rate analysis at higher frequencies.