The First Observations of Cherenkov's Radiation of Runaway Electrons Produced by Discharge in Dense Gas

For the first time, Cherenkov's radiation (CR) was detected of runaway electron (RE) pulse generated by electric discharge in open atmosphere. The measured duration of the CR pulse is Δt
_0.5
≈ 0.4 ns, the intrinsic duration does not exceed the measured duration of the pumping RE pulse At
_0.5
≈ 0.15 ns. The observations of CR, executed with Plexiglas radiator, testify that the RE spectrum is stretched above the CR threshold in Plexiglas 176.4 keV.