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The magnetized liner inertial fusion (MagLIF) approach to inertial confinement fusion [1] involves subsonic/isobaric compression and heating of a deuterium-tritium plasma with frozen-in magnetic flux by a heavy cylindrical liner. In order to understand the transport of magnetic flux, a recent paper [2] developed self-similar solutions in one dimension for the loss of heat and magnetic flux from a...
The Rayleigh-Taylor (RT) instability and related hydrodynamic mechanisms of interfacial mixing are ubiquitous in nature, occurring on a large variety of scales, from atmospheric and oceanic to supernovae. They are of particular importance for many applications that involve high energy density plasmas, such as Z-pinch plasma sources of x-ray and neutron radiation or inertial confinement fusion (ICF)...
One component of the MagLIF approach to inertial fusion ignition involves compression and heating of a DT plasma with frozen-in magnetic flux by a heavy cylindrical liner. The liner implosion velocity most of the time is lower than the speed of sound in the compressed DT plasma, which makes the plasma motion subsonic and isobaric. The losses of heat and magnetic flux from the plasma are thereby determined...
We have reestablished gas puff z-pinch capability on Sandia's 20 MA Z machine, including a Sandia-operated driver system and an imaging interferometer to characterize nozzle mass flow [1]. Initial experiments have focused on developing a 3 keV Ar K-shell x-ray source. We have pursued a design-driven approach to planning these experiments, utilizing numerical simulation to predict Ar K-shell yield...
It had been noticed long ago1 that the requirements for inertial confinement fusion (ICF) ignition in a cylindrical target can be significantly relaxed if the plasma were compressed simultaneously with the flux of the entrained magnetic field from its seeded value ∼100 kG to the peak value of ∼100 MG. The ultrahigh axial magnetic field insulates the hot spot from the cold walls compressing it and...
Argon z-pinch experiments are to be performed on the refurbished Z machine at Sandia National Laboratories with a new 8 cm diameter double-annulus gas puff nozzle constructed by AASC. The gas exits the nozzle from an outer and inner annulus and a central jet. The amount of gas present in each region can be varied. Here we employ a two-dimensional radiation MHD model to theoretically investigate stability...
Advanced simulations of high energy density plasma involve 2D and 3D computer codes. To ensure reliable results such codes should be subjected to verification tests, i.e., compared against exact analytic solutions. The present work examines the appropriateness of the 3D Cartesian code Athena for modeling stagnating Z-pinch implosions. The classic problem of a strong, self-similar expanding shock accreting...
Recent 3D RMHD simulations [1] and experiments [2] have demonstrated that axially and azimuthally averaged dynamics of a strongly radiating stagnated Z-pinch column resembles a self-similar, cylindrically symmetric motion. The cold, rapidly imploding incident plasma transforms into the hot stagnated plasma when it gets heated and compressed in the diverging shock wave that propagates from the pinch...
When a multi-Mbar shock wave propagates into a laser target from a rough or non-uniformly irradiated surface, the shock front after a few rapidly decaying oscillations becomes planar. Much stronger oscillations of the shock front and the shocked mass have been theoretically predicted [1] for the case when the shock front is unsupported. For example, after a short (sub-ns) laser pulse deposits finite...
Summary form only given. Doppler-broadened lines with large widths, indicative of ion energies much higher than the thermal electron energies, are sometimes observed in Z pinches. In some Z-pinch experiments, these large energies are likely due to a high ion temperature, but turbulence may dominate in others. The rate of the aneutronic fusion reaction 3He+D→4He+H+18.4 MeV, is near its maximum at ion...
It has been experimentally demonstrated that deuterium gas-puff implosions at >15 MA are powerful sources of fusion neutrons.1 Analysis of these experiments2,3 indicates that a substantial fraction of the obtained DD fusion neutron yields ~3xl013, about 50%, might have been of thermonuclear origin. The goal of our study is to estimate the scaling of the thermonuclear neutron yield from deuterium...
A series of Al/Mg nested wire array Z-pinch load experiments has been recently performed on the refurbished Z accelerator. The earlier comparison study of the results from ID and 2D radiation MHD simulations of the Sandia Z1907/1908 experiments [Y. K. Chong, et. al, APS09] has shown that, in addition to the substantial difference in the prediction capability of the ID and 2D models, the radiation...
We have developed uniform-fill nozzles for long-implosion PRS experiments to produce argon K-shell x-rays (photon energy > 3.1 keV). With a 7 cm diameter nozzle, which is appropriate for a 200 ns driver, we have achieved a stable implosion at 180 ns and 4 MA with peak argon K-shell yields exceeding 15 kJ. As previously seen with short (∼100 ns) implosion times, the K-shell yield scales as the fourth...
We report on the experimental operation of an argon double gas puff. The experiments were performed on the 200 ns, 4 MA Double-EAGLE facility at Maxwell Physics International. Extensive diagnostics demonstrated good quality implosions comparable in quality to short pulse (∼100 ns) z-pinches.
A load structure with tailored density profile which delays the onset of the Rayleigh-Taylor instability development in imploding Z-pinches by inverting acceleration of the magnetic field/plasma interface is proposed and studied numerically. This approach makes it possible to start gas-puff implosions from large radii (like 8 cm) and produce significant K-shell yield with current pulse duration of...
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