Stagnation of a gas puff Z pinch

Summary form only given. MHD simulations of a gas puff Z pinch are carried out, in order to elucidate the stagnation process, and compare qualitatively with recent experimental measurements. The simulations are motivated by results of a recent experiment [1]. Additional simulations will be presented of a three dimensional gas puff Z pinch with an applied axial magnetic field, which will be compared to an experiment in preparation. Simulations were performed with the M3D code [2]. In the case without an applied field, or with a sufficiently small axial field, the plasma core in stagnation expands from zero and then contracts, similar to experimental observation. The time scale for this is the stagnation radius divided by the sound speed in the stagnated plasma. In turn the sound speed is comparable to the Alfven speed.