Tuesday, March 21, 2017

Abstract-Threshold Conditions for Terahertz Laser Discharge in Atmospheric Gases

V. V. Kubarev, Ya. V. Getmanov, O. A. Shevchenko, P. V. Koshlyakov,


In this study, we accurately measured the breakdown thresholds in four atmospheric gases using the high-power terahertz radiation of the Novosibirsk free electron laser (NovoFEL). The breakdown intensities of the 130-μm radiation in a form of 74-ps pulses were equal to 1.1–1.4 GW/cm2. These data have been compared with calculations based on a phenomenological criterion for a breakdown and the classical theory of stochastic microwave heating of electrons. Presented are threshold conditions for a quasi-continuous plasma discharge that is maintained by means of a sequence of pulses of the NovoFEL. At a pulse repetition rate of 5.6 MHz, the discharge quenching thresholds are 15–60% lower than the breakdown thresholds depending on the amount of plasma emerging

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