LIF measurements of a low-power helium arcjet

Summary form only given. We are interested in measuring the plasma properties of the helium arcjet flowfield. A number of different diagnostic have been developed to investigate the arcjet plasma plume. Among these diagnostics, laser-induced fluorescence (LIF) has proven to be very useful due to it spatial resolution and species specific nature. This paper presents the results of LIF measurements of the velocity and temperature of the arcjet flowfield. From previous studies, the arcjet flowfield is known to have electron number densities in the range of 10/sup -12/ cm/sup 3/ and electron temperatures of 0.2-0.5 eV. In the preliminary study of the helium arcjet, velocities between 9 and 15 km/s were measured 7 cm downstream of the exit plane with temperatures between 300 and 900 K. In this study, the 587.5 nm transition will be used. A dye ring laser using Rhodamine 6G pumped by a 5 W argon-ion laser will be used to probe this transition. By comparing the measured line center position with that of a stationary reference source, the Doppler shift was measured and converted into an axial velocity. The FWHM of the lineshape will be used to determine the translational temperature.