Microwave Radiation Associated with Lightning Initiation Events of Negative Cloud-to-Ground Flashes

In this paper, we examined the initiation events of ten negative cloud-to-ground (CG) flashes detected close to measurement stations on 12 November (CG-1 CG-5) and 24 (CG-6 CG-10), 2019. All CG were accompanied by microwave very-high frequency (VHF) radiation pulses. We recorded all from two (ST1 ST2), which are separated 13.3 km consist fast slow antenna (FA SA) sensors, a magnetic field (B-field) sensor, VHF sensor (60 MHz), (~1 GHz). The key finding is that pulses before onset initial electric changes (IECs) preceded with an average lead time 1.53 µs, ranging between 0.3 3.0 µs (for within reversal distance). A total 50%, 17%, 33% initiated single pulse, pulses, three respectively, followed IECs. Some classified as short (pulse duration less than 0.5 µs). first IECs 53.4 32.78 respectively. suggested be emitted short-length positive streamers. Because earlier (average µs) it most likely electron avalanche process.