Optical spectroscopy of a plasma opening switch on Ace 4

Summary form only given. We report on emission spectroscopy of a coaxial plasma opening switch (POS) operating at a current of over 2 megamps and conduction times of over a microsecond. Spectroscopy can be a strong complement to other POS diagnostics, enhancing understanding of the POS plasma and of the MHD snowplow conduction process. We used a microchannel gated CCD camera in the focal plane of a 1.33 meter spectrograph. The entrance slit of the spectrograph is imaged via fiber optics into an axial view, from the load side, of the POS conduction volume. The camera has /spl sim/100 ns time resolution for studies at wavelengths between 200 nm and 800 nm.