Characteristics of Double Probe in Negative Ion-Containing Plasmas

Abstract

Analysis of current-voltage characteristics of a generalized asymmetric double probe is made for plasmas containing negative ions. Characteristics are insensitive to negative ions up to a critical negative ion density ratio (>0.9), and tend to obey the tanh formula below this ratio. This critical value increases with higher negative ion mass. Applicability to negative-ion diagnostics is also considered.