LaB6 cathode for Divertor Plasma Simulator(DiPS)

Abstract

The Divertor Plasma Simulator (DiPS) is developed for the studies on electric probes, plasmawall interactions, atomic processes in recombining plasma and plasma diagnostic tool development with the steady-state high density LaB6 dc plasma source. Since the LaB6 is very weak against with the thermal shock, the source is considered as low as possible the thermal stress to stable operation. The thermal arc possibly caused due to overflows the discharge current in a flash, which is a fatal to crack the LaB6 plate, can be reduced by adjusting the magnetic field, electric field configuration with floating electrode. The LaB6 source is composed of the 4 in diameter cylindrical LaB6 plate, graphite heater and Ta heat shield. From the different electric field & magnetic field configuration, the LaB6 dc plasma source is optimized with the electron density 1014 cm.3 (Ar), 1013 cm.3 (He), electron temperature=2-3 eV (Ar), 5-10 eV (He) and ion temperature=0.1 - 0.2 eV (Ar).