Measurements of Argon-ion Flow in Negative Ion Containing Plasmas

A laser-induced-fluorescence diagnostics was set up for the investigation of ion flows in negative ion containing plasmas. The contingent of negative ions in Ar plasmas is varied by admixing O2. Results on flow measurements in different plasma devices are reported. First measurements were carried out in the linear double-plasma device, in the sheath region in front of an electrically floating plate, where negative ions are expected to modify the sheath potential and, hence, the ion flow to the wall. In a second step, LIF is used to characterize Ar-ion flows and temperatures in the toroidally confined plasma of the torsatron TJ-K with the aim to study the influence of negative ions on drift-wave turbulence in fusion edge plasmas.