Experimental Investigation of Plasma Formation and Evolution from an Aluminum Surface Driven by a MG Field

Summary form only given. The physics of plasma formation by extremely high pulsed magnetic fields is important in wire-array Z-pinches, high current fuses, magnetically insulated transmission lines, ultrahigh magnetic field generators, magnetized target fusion, and astrophysics. To study the behavior of conductors exposed to MG fields, an experiment has been performed on Zebra, a 2-TW pulsed-power driver with a peak current of 1 MA. Plasma formation by ohmic heating, typical of numerical modeling, can be obscured by plasma formation induced by arcing at electrical contacts or by high electric fields. To avoid this, a new type of aluminum load was developed and compared with 1-mm-diameter wire loads: loads machined from a solid aluminum cylinder. These hourglass-shaped machined loads have large-diameter flanges at the top and bottom and a 1-mm-diameter thinned "wire" section in the center. The flanges provide enlarged contact circumference thereby avoiding arcing. The wire section was diagnosed by a time-gated intensified CCD camera, a streak camera, photodiodes, and photomultipliers. In addition, laser shadowgraphy, schlieren, interferometry and Faraday rotation diagnostics were employed. Also see papers presented by T. Awe, B. Bauer, A. Esaulov, and V Makhin at this conference for additional modeling and experimental results.