Measurement of Plasma Parameters using Electric Probe Method and Laser Induced Fluorescence in the Space Propulsion Simulator

Abstract

The space propulsion simulation has been developed with VASIMR concept. The open-ended mirror field was produced by 7 magnetic coils. Helicon plasma source was installed and generated with m=+-1 right-helical antenna at 13.56 MHz with rf power up to 3 kW. The typical helicon plasma parameters, such as electron temperature, ion temperature, plasma density, flow velocity and magnetic field strength were measured by LIF system and a fast scanning electric probe system composed of an rf-compensated single probe and a Mach probe. The mode transition from inductively coupled plasma to helicon plasma was observed. Typical plasma parameters are found as the following: n = 10^11 - 10^13 cm-3, Te = 6-8 eV, Ti = 0.14-0.17 eV, and vd (drift velocity) = 0.8-1.55 km/s.