Study of THz Gas Discharge Spatial Dynamic in Argon

A compact interferometer was developed and created for studying the spatial-temporal dynamic of a terahertz discharge in argon. It has been shown that the plasma density exceeds the cut-off value for the given frequency of radiation sustaining the discharge. This article discusses the issues of neutral displacement from the discharge region and investigates the dynamic of displaced particles in a wide range of background pressures. A gyrotron with a maximum pulse power of 40 kW at a frequency of 0.67 THz with a pulse duration of 20 \mu \text{s} was used to create a gas discharge.