Nowadays cosmic and earth-based nuclear power industry specifies stringent requirements to the research and development sector in view of its necessity for the total control over the current density, smooth failure-free operation of energy-generating plants under extreme conditions at high radiation levels and temperatures above 1000 K. The application of high-current thermionic cesium-barium switching devices meets one of those requirements. The results of the research into plasma's electro kinetic parameters of Knudsen high-current diode and triode switching devices are presented below.