Current Distribution in Liner-on-target Gas-Puff Implosions on the CESZAR Linear Transformer Driver*

Gas-puff Z-pinches serve as powerful x-ray and neutron sources and have been studied in a number of configurations for their potential use in nuclear fusion. Understanding the Z-pinch process necessitates diagnosis of the evolution and behavior of the currents and magnetic fields which drives the implosion. Liner-on-target gas-puff (an annular jet surrounding a central column jet) z-pinches experiments have been performed on the CESZAR linear transformer-driver (500 kA and 160 ns current rise time) at UC San Diego using a Zeeman-based polarization spectroscopy technique to measure the azimuthal magnetic field both in the target and liner regions. Values of B_θ were measured up to 4 T in the target regions and up to 8 T in the liner region. In addition, a fast-framing extreme ultra-violet camera provided information about pinch dynamics. Experimental measurements of the azimuthal magnetic field and implosion dynamics are compared with the magnetohydrodynamic simulations carried out in HYDRA.