Experimental and theoretical study of ion reflection for new diagnostic method of ion energy distribution in edge plasma

A new diagnostic method to measure ion energy distribution using ion reflec tion on the solid surface, one of the processes of plasma-wall interactions , is proposed. It is well known that the energy distribution of reflected p articles is related to the energy distribution of incident ions. This metho d is used in relatively low ion temperature region such as edge plasma in f usion experimental devices. Incident ions to target plate which is inserted in the edge plasma are mainly reflected as neutral particles, and time-of- flight method is utilized to measure energy distribution of reflected parti cles. Energy distribution of incident ions is deduced by fitting with calcu lation using Monte Carlo simulation code TRIM.SP. The sheath potential in f ront of the target can also be obtained with this method.