Azimuthal Clumping Instability in Wire Array Z-pinches

POSTER

Abstract

UM and Sandia have analyzed an azimuthal clumping instability that bunches discrete wires in z-pinches. Highest instability growth rate is pi-mode: wires clumped in pairs. An efficient discrete wire code agrees with analytic theory, showing bunching in sub-100 ns, close to MA z-pinch risetimes. Using Sandia ALEGRA code, wire arrays are simulated utilizing a wedge-shaped sector with reflective boundary conditions. By choosing the wedge sector angle, pi-mode growth of the clumping instability is studied for a given wire number by simulating only a single wire within that wedge. A non-linear analytic theory shows excellent agreement with both ALEGRA and discrete wire codes for high ($\sim $600) and low (8) wire-number arrays. Results are presented of azimuthal clumping experiments on Cornell COBRA.

*Supported by DoE through Sandia National Labs subcontract to UM. Cornell supported by Stewardship Sciences Academic Alliances program of National Nuclear Security Administration under DOE Cooperative agreement DE-FC03-02NA00057.

Authors

  • T. Strickler

  • W. Tang

  • Y.Y. Lau

    • University of Michigan

  • R.M. Gilgenbach

  • M.R. Gomez

  • J. Zier

    • Nuclear Engineering and Radiological Sciences Dept., University of Michigan, Ann Arbor, MI

  • E. Yu

  • C. Garasi

  • T.A. Mehlhorn

  • M.E. Cuneo

  • M.G. Mazarakis

    • Sandia National Laboratories, Albuquerque, NM

  • D.A. Chalenski

  • J.D. Douglass

  • J.B. Greenly

  • D.A. Hammer

  • B.R. Kusse

    • Laboratory of Plasma Studies, Cornell University, Ithaca, NY