Mass separation in a 100-ns plasma opening switch

Summary form only given. The behavior of the different ion species that make up multicomponent plasmas can affect the results of various laboratory experiments and is important for understanding phenomena in space plasmas. We study the motion of various plasma ions in a 100-ns, 170-kA Plasma Opening Switch (POS) by observing the time dependence of the electron density and the ion velocity distribution. The prefilled-plasma composition is determined from absolute line intensities and collisional-radiative calculations. Close to the inner electrode, most of the plasma ions are protons (as high as 90%) with the rest being mainly CIV. Near the outer electrode, there is a much larger fraction (/spl ap/50%) of non-protonic species. The prefilled-plasma density and temperature are almost constant at all radii, where n/sub e/=(2.2/spl plusmn/0.5)/spl times/10/sup 14/ cm/sup -3/ and T/sub e/=5.5/spl plusmn/1 eV.