POSITIVE IN EXTRACTION BY AN ANODIC ORIFICE PROBE

From a nonthermal plasma ions are extracted by an orifice probe being anodic, i.e. positive with respect to plasma potential. In front of the orifice a secondary plasma is observed providing an intense source for ion extraction. The extraction mechanism can be explained by a potential of the secondary plasma above probe potential. The thermal energies of the ions from the secondary plasma are of the order of 1/10 eV