Characterization of Z-Pinch Loads by using Laser Induced Fluorescence and Laser Shearing Interferometer

Abstract

Summary form only given. Because the energy coupling and the X-ray output of Z-pinch plasma radiation sources are determined by the implosion history, measurements from the initial gas phase, through the MHD implosion phase, to the final pinch phase are needed. Many diagnostics have been developed for the final pinch phase. We have developed a planar laser induced fluorescence (PLIF) technique to characterize the gas puff in the initial phase and demonstrated a laser shearing interferometer (LSI) approach for the implosion and pinch phases on a high current accelerator. These laser based instruments have the advantages of being user-friendly and giving the data quickly. Using the PLIF method, the 2-D gas density and flow velocity profiles of the loads were obtained with sub-mm spatial resolutions for the conditions used in the Z-pinch experiments. From the LSI, the shape of the imploding plasma was determined and the wavelengths of the Rayleigh-Taylor instability were measured. We have also found that the pinch plasma sizes are about twice that measured from the K-shell X-ray pinhole images. The combination of the PLIF and (LSI) measurements enable us to better understand the implosion dynamics and to provide important information needed for simulation codes