Lightning electromagnetic radiation field spectra in the interval from 25 to 100 MHz

Abstract

By means of a fast Fourier transform (FFT), average energy spectra in the interval from 25 to 100 MHz are presented for most of the components that produce large radiation field pulses from lightning: first and subsequent return strokes; stepped and dart leaders; preliminary breakdown and Intracloud K changes.

Superconducting protector against electromagnetic pulses based on YBCO film prepared on an Al2O3 substrate with a CeO2 sublayer

“…Moreover, they also need to induce as low as possible an initial attenuation of the useful signal and to be ready to operate after each EMP event. In the case of a nuclear EMP or an EMP generated by lightning, the fault overvoltage pulse induced in the receiving antenna's output consists of powerful high frequency components (hundreds of megahertz to several gigahertz) [1,14] and has relatively long (up to tens of milliseconds) low frequency 'tails'. Thus, protectors against this type of EMP have to react in subnanosecond times and to be able to withstand large energy absorption shocks during these EMP 'tail' periods.…”