Characterization of Zirconium Cathode Arc-Heater Plume by Laser Absorption Spectroscopy

Abstract

An arc-heater with pre-mixed gas injection system of argon and oxygen has been developed and its performances were characterized. To reduce the cathode erosion zirconium was used as a cathode material. Consequently, stable discharge was maintained for more than three hours with small cathode erosion rate of 1.7x10-5 g/s, which corresponds to the erosion speed of the cathode surface of 0.27 mm/hour. From LAS diagnostics, oxygen was found fully dissociated in the center of plume at the radial position less than 6 mm. The atomic oxygen flux and the total specific enthalpy around the centerline were estimated at 3.1x10 19 atom/cm 2 s, 4.5±0.1 MJ/kg, respectively.