Properties of unipolar magnetic field pulse trains generated by lightning discharges

Abstract

[1] We analyze and describe trains of regular unipolar microsecond-scale magnetic field pulses produced by intracloud lightning discharges. Waveforms of the magnetic field are measured using a newly developed broadband analyzer with a sampling interval of 12.5 ns. The observed trains contained several tens of pulses, and the time interval between neighboring pulses typically varied between 1 and 10 ms. The amplitude of the pulses also varied by 1 order of magnitude. A systematic analysis of these variations is done for the first time. The interpulse interval is usually increasing (on average by 4.1 ms during a train), and the pulse amplitude is decreasing (on average by 15% of the maximum value within a given train). We propose a possible generation mechanism based on a hypothesis that periodical charge structures are present in the thundercloud. This mechanism can explain the observed evolution of peak amplitudes and interpulse intervals. Citation: Kolma sová, I., and O. Santolík (2013), Properties of unipolar magnetic field pulse trains generated by lightning discharges, Geophys. Res. Lett., 40,

Subionospheric propagation and peak currents of preliminary breakdown pulses before negative cloud‐to‐ground lightning discharges

“…For the magnetic field measurements we use a shielded loop antenna connected to a ground-based version of a broadband (5 kHz-37 MHz) analyzer [Kolmašová and Santolík, 2013] which was developed for the TARANIS spacecraft [Blanc et al, 2007]. The sampling rate is 80 MHz.…”

On the Possible Origin of Chaotic Pulse Trains in Lightning Flashes

“…If we consider any pulse with an opposite overshoot to be bipolar, then almost all the pulses we observed in the present study can be categorized as bipolar. However, in a study conducted by Kolmasova and Santolik [10], each individual pulse is considered to be unipolar if the immediately following overshoot of the opposite polarity does not exceed one-half of the peak amplitude of the original's pulse. If we use this criterion, then most of the individual pulses in the RPT should be categorized as unipolar.…”

Electron acceleration above thunderclouds

“…µs are superimposed on the radio signal from the cloud to ground lightning discharge (figure 3) as observed with high frequency magnetic field recordings from ∼5 kHz-40 MHz(Kolmasova and Santolik 2013) near Rustrel (43.9 • N, 5.5 • E) at a distance of ∼40 km north-east of the initial sprite and ∼16 km south-west of the second positive lightning discharge. The second positive lightning discharge with the resonance ll The high frequency magnetic field measurements from ∼5 kHz-40 MHz near Rustrel (RST) show that the second positive lightning discharge (upper panel) exhibits resonant type oscillations with a period of ∼3.8 µs (∼260 kHz) lasting for ∼9 cycles over ∼34.2 µs (lower panel) attributed to a bouncing-wave discharge.…”

“…This pulsed discharge event was initially discovered by high frequency magnetic field recordings with a ground based doublet of a high frequency receiver (Kolmasova and Santolik 2013) which is being developed for the TARANIS spacecraft (Blanc et al 2007). It was the only high frequency event recorded during the passage of the thunderstorm.…”