Spectroscopic analysis of foil plasmas on a 1-MA Linear Transformer Driver

Summary form only given. Spectroscopic analysis has been performed on Al foil plasmas ablated by the Linear Transformer Driver (LTD) at the University of Michigan. The MAIZE LTD can supply 1-MA, 100 kV pulses with 100 ns risetime into a matched load. The plasma load used in this experiment consists of a 400 nm Al foil (cathode) placed between two, planar, current return anode posts. The LTD was charged to +-70 kV, resulting in approximately 0.65 MA with a 170 ns risetime passing through the foil. An optical fiber was placed about 1 cm away from the load; plasma light passed through a 0.75-m optical spectrograph and was gated for 10 ns by an intensified CCD detector. The density of the edge plasma can be determined through Stark broadening of the H-alpha line. The Fourier transform was taken of the Voigt profile, which was then used to approximate the density of the Al plasma. This method resulted in a density of approximately 10¹⁵ cm^-3 in the outer regions of the Al plasma at peak current. Additionally, spectra taken during the current rise yielded 1-3-eV plasma temperatures from the slope of the continuum emission. These data will be shown as well as planned future experiments.