Pulsed-power-driven high energy density physics and inertial confinement fusion research

Abstract

The Z accelerator [R. B. Spielman, W. A. Stygar, J. F. Seamen et al., Proceedings of the 11th International Pulsed Power Conference, Baltimore, MD, 1997, edited by G. Cooperstein and I. Vitkovitsky (IEEE, Piscataway, NJ, 1997), Vol. 1, p. 709] at Sandia National Laboratories delivers $\sim 20\mathrm{MA}$ load currents to create high magnetic fields $(>1000\mathrm{T})$ and high pressures (megabar to gigabar). In a $\mathrm{z}$ -pinch configuration, the magnetic pressure (the Lorentz force) supersonically implodes a plasma created from a cylindrical wire array, which at stagnation typically generates a plasma with energy densities of about $10\mathrm{MJ}∕{\mathrm{cm}}^3$ and temperatures $>1\mathrm{keV}$ at 0.1% of solid density. These plasmas produce x-ray energies approaching $2\mathrm{MJ}$ at powers $>200\mathrm{TW}$ for inertial confinement fusion (ICF) and high energy density physics (HEDP) experiments. In an alternative configuration, the large magnetic pressure directly drives isentropic compression experiments to pressures $>3\mathrm{Mbar}$ and accelerates flyer plates to $>30\mathrm{km}∕\mathrm{s}$ for equation of state (EOS) experiments at pressures up to $10\mathrm{Mbar}$ in aluminum. Development of multidimensional radiation-magnetohydrodynamic codes, coupled with more accurate material models (e.g., quantum molecular dynamics calculations with density functional theory), has produced synergy between validating the simulations and guiding the experiments. Z is now routinely used to drive ICF capsule implosions (focusing on implosion symmetry and neutron production) and to perform HEDP experiments (including radiation-driven hydrodynamic jets, EOS, phase transitions, strength of materials, and detailed behavior of $\mathrm{z}$ -pinch wire-array initiation and implosion). This research is performed in collaboration with many other groups from around the world. A five year project to enhance the capability and precision of Z, to be completed in 2007, will result in x-ray energies of nearly $3\mathrm{MJ}$ at x-ray powers $>300\mathrm{TW}$ .