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Subionospheric propagation and peak currents of preliminary breakdown pulses before negative cloud‐to‐ground lightning discharges
Author(s) -
Kolmašová Ivana,
Santolík Ondřej,
Farges Thomas,
Cummer Steven A.,
Lán Radek,
Uhlíř Luděk
Publication year - 2016
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 - 10.1002/2015gl067364
Subject(s) - lightning (connector) , amplitude , electromagnetic pulse , thunderstorm , electric field , waveform , ionosphere , physics , geophysics , geology , meteorology , optics , voltage , power (physics) , quantum mechanics
We analyze broadband electromagnetic measurements of pulse sequences occurring prior to first return strokes of negative cloud‐to‐ground lightning flashes. Signals generated by lightning discharges were recorded close to the thunderstorm by a magnetic field receiver and traveled up to 600 km to three distant electric field receivers. We found that amplitudes of observed preliminary breakdown pulses, as well as amplitudes of the corresponding return strokes, are attenuated approximately by 2 dB/100 km when propagating in the Earth‐ionosphere waveguide over mountainous terrain. Propagation simulations show that there is a significant contribution of the sky wave signals in the waveforms observed beyond 500 km from their source. The estimated peak currents of the largest preliminary breakdown pulses reach over 60 kA. Such current pulses propagating through in‐cloud lightning leader channels in a strong electric field may be able to initiate terrestrial gamma ray flashes.