Generation of anomalous electrons during high-voltage nanosecond breakdown in dense gases

High-voltage nanosecond breakdown in dense gases is accompanied by the generation of anomalously fast electrons with energies exceeding that ensured by the voltage applied to the discharge gap. Previously, the appearance of such electrons was explained by a polarization self-acceleration at the streamer head. In this Letter, a model of squeezed capacitor is proposed that explains the generation of anomalous electrons under conditions where no spark channels are formed.