Graphite as a structural material for the in-vessel components for plasma diagnostics in the millimeter and sub-millimeter ranges

Abstract

The possibility to use the carbon-graphite materials (CGM) instead of metals for fabrication of the in-vessel components for plasma diagnostics in the mm and sub-mm ranges on large-scale fusion devices was investigated. The reflectivity of different kinds of CGMs (more than 20) was measured in the wavelength range of 10 pm-30mm and was found to be only little below the values for metal analogues. The effects of surface roughness, pulsed plasma impact, heating and neutron irradiation on the retlectivity of CGM-made reflectors were analyzed. The role of graphite protection of the first wall in the energy balance in a fusion reactor was evaluated using the reflectivity data obtained. The working characteristics of antennae, waveguides and resonator fabricated of CGMs are presented as measured before and after pulsed plasma impact and/or heating up to 1 oooc.The CGM-made diagnostic components demonstrated much stronger resistance to pulsed power plasma impact than metal-made ones and at the same time reasonable working characteristics. Therefore they can successfully replace the metallic components in cases when similar (h., CGM) materials are used for the first wall protection.