First observations of runaway breakdown phenomenon in laboratory experiments

Abstract Microwave electron cyclotron resonance discharge in air is studied in a time-varying magnetic mirror trap. The obtained experimental data demonstrate a rapid increase in the number of fast electrons with wide energy spectrum (1–300 keV). It is followed by strong flashes of γ photons and associated secondary optic emission. The experimental results are interpreted as the first observation in a laboratory of the runaway breakdown phenomenon, which plays a significant role in a thunderstorm atmosphere.