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 ∼20MA load currents to create high magnetic fields (>1000T) and high pressures (megabar to gigabar). In a 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 10MJ∕cm3 and temperatures >1keV at 0.1% of solid density. These plasmas produce x-ray energies approaching 2MJ at powers >200TW 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 >3Mbar and accelerates flyer plates to >30km∕s for equation of state (EOS) experiments at pressures up to 10Mbar 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 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 3MJ at x-ray powers >300TW.

Determining the refractive index of shocked [100] lithium fluoride to the limit of transmissibility

“…To determine the refractive index of LiF at higher stress than are possible with the 2-stage gun, we utilized the flyerplate capability developed on the Sandia Z Machine, 22 a pulsed power accelerator capable of generating $20 MA currents and $10 MGauss magnetic fields in a short-circuit load (Fig. 2).…”

Experimental astrophysics with high power lasers andZpinches

“…These include high power lasers and fast magnetic pinch machines ͑"Z pinches"͒, which were developed largely as a result of the national inertial confinement fusion ͑ICF͒ program ͑Lindl et Matzen et al, 2005͒. Hand in hand with the emergence of these HED experimental facilities came the realization that a new class of laboratory astrophysics could be pursued ͑Ripin et al, 1990;Rose, 1991;Drake, 1999;Remington et al, 1999Remington et al, , 2000Takabe,Measurements of these conditions and their evolution, when properly diagnosed, allow theoretical models and computer simulation codes to be tested under the extreme conditions relevant to HED regimes of astrophysics. Examples include measurements of ͑i͒ opacities relevant to stellar interiors ͑Rogers and Iglesias, , 1998Arnett, 2001;Bailey et al, 2002;Chenais-Popovics, 2002;Wang et al, 2004͒, ͑ii͒ the phase, conductivity, and equations of state of matter under conditions relevant to planetary interiors ͑Celliers et Knudson et al, 2004;Saumon and Guillot, 2004͒, ͑iii͒ scaled, strong-shock-driven turbulent dynamics relevant to supernova explosions ͑Robey, Zhou, et al, 2003;Drake, Leibrandt, et al, 2004;Miles, Braun, et al, 2004͒; and ͑iv͒ ionization states of radiatively pumped photoionized plasmas relevant to accretion disks surrounding black holes or neutron stars ͑Foord et al, 2004͒.…”

An Evaluation of a Structured Overlapping Grid Implementation of FCT for High-Speed Flows

“…This stagnation and subsequent magnetic energy conversion produces an intense 10 ns X-ray radiation pulse [43,53]. The intense X-ray pulse can then be used for radiation-material interaction studies [44,42,45], environments for indirect drive inertial confinement fusion (ICF) applications [42,45,43], or for pursuing laboratory-based astrophysics environments [45,51,54,15,9,22]. An important limiting mechanism for the amount of radiation energy produced by a Z-pinch is the Magnetic Raleigh-Taylor (MRT) instability which distorts the outer and inner interfaces of the collapsing plasma shell and broadens the pulse width [42,45,23].…”

“…The induced local plasma current, J and magnetic flux density, B, produces a strong J × B Lorentz force which accelerates a highly energetic plasma to stagnate on axis in about 100 ns. This stagnation and subsequent magnetic energy conversion produces an intense 10 ns X-ray radiation pulse [43,53]. The intense X-ray pulse can then be used for radiation-material interaction studies [44,42,45], environments for indirect drive inertial confinement fusion (ICF) applications [42,45,43], or for pursuing laboratory-based astrophysics environments [45,51,54,15,9,22].…”