Concerning Feasibility of Water Microleakage Diagnostics by Auto-oscillating Discharge

One of the perspective methods of water microleakages detection in thermonuclear devices is presented. Method is based on the secondary electron emission instability of Debye near-electrode layers in the contact of nonequilibrium plasma with electrode surface covered by thin dielectric film. Method is based on detection of beam-plasma discharge transition into auto-oscillation regime. It is observed when balance between oxidation and sputtering of a contact surface covered by thin dielectric film is shifted. The method has better sensitivity (< 1016 mol/s) and response time (< 60 s) as compared with spectroscopic methods (> 1016 mol/s and > 2000 s, respectively). In addition, it allows detecting negligible oxygen-containing admixture. In perspective, this method will allow to localize a water microleakage in vacuum chambers of thermonuclear devices and determine a water vapor flow by features of IV-curve.