Electric Probe Systems for Diversified Plasma Simulator (DiPS)

초록

DiPS(Diversified Plasma Simulator), a new versatile linear machine (length=4000mm, diameter=200-600mm), is developed for the simulation of divertor, space and processing plasmas with various electric probes: fast-scanning single probe, triple probe, Mach probe, slow-scanning water-cooled single probe, gridde-energy analyser, GET(Gundestrup-Emissive-Triple) probe, and several fixed single probes. For the verification of current probe theories and develop new theories with magnetic field, collisionality, various particle sources, and wide range of plasma parameters, two different plasma sources are installed: (1) For a stable high density dc plasma, LaB6 disk is used as thermal electron emission source with 5 kW graphite heater. Initial plasma density of the LaB6 source is 5ⅹ10^12 cm^-3, electron temperature is 8-10eV with magnetic field around 1 kG. Density would be decreased severely with grid and expanded into space simulation region without magnetic field. (2) Helicon plasma source is also installed for a processing simulation in DiPS and for the space propulsion study with magnetic expansion, which generates the plasma with density of 2ⅹ10^13 cm^-3 and electron temperature 3.5eV for the rf power of 2.5kW at optimum pressure of 7.5mTorr. As a unique feature for the diversified uses of sources and divertor simulator experiments, space and processing simulation chambers can be detached from and attached to the divertor simulation chamber by rail. Along with initial data of various electric probes, the laser-induced fluorescence and optical emission spectroscopic methods are to be introduced for the calibration of flow velocity and ion temperature measurements