Electrode-expansion MHD in a plasma-filled rod pinch

The Gamble II plasma-filled rod pinch (PFRP) produces an order-of-magnitude higher x-ray dose and smaller FWHM source size than achieved with a vacuum rod pinch. Intense electron deposition at the tip produces a high-energy-density expanding-tungsten plasma, the bremsstrahlung from which creates a low-intensity halo around the source core that increases the effective source size for some applications. The plasma motion has been measured with a holographic interferometer. Using the distribution of electron deposition derived from line-spread measurements, the observations are compared with zero-and one-dimensional self-similar MHD modeling of the plasma motion. Results demonstrate that magnetic-field and ohmic-heating effects during electron deposition are important to understanding PFRP dynamics.