Simulations of Gas-Puff Z-Pinch Implosions with comparison to Magnetic Fields measurements at the Weizmann Z-Pinch.*

Measurements of magnetic field in gas-puff implosions on the generator at the Weizmann Institute of Science (WIS) have been recently shown to be in contradiction to a snowplow model using the current of the pulsed-power generator and the pinch radius. Simulations of magnetic field evolution using the 2D radiation-magneto-hydrodynamic code, MACH2-TCRE are presented in two steps as follows. In the first step, simulations of the initial density profile by modeling the neutral gas-flow of subsonic oxygen through De-Laval nozzles are made and compared to measurements. In the second step, the density profiles from the previous step are used as initial conditions for investigating the distribution evolution of the magnetic field during the gas-puff implosions. Comparisons are made with the measured data of magnetic field and radius. It is shown that simulating the nozzle geometry and outflow significantly improves the comparison between the measurements and the pinch simulations.