Atlas will be a high-energy (36 MJ stored), high-power (/spl sim/10 TW) pulsed power driver for high energy-density experiments, with an emphasis on hydrodynamics. Scheduled for completion in late ...1999, Atlas is designed to produce currents in the 40-50 MA range with a quarter-cycle time of 4-5 /spl mu/s. It will drive implosions of heavy liners (typically 50 g) with implosion velocities exceeding 20 mm//spl mu/s. Under these conditions, very high pressures and magnetic fields are produced. Shock pressures in the 50 Mbar range and pressures exceeding 10 Mbar in an adiabatic compression will be possible. By performing flux compression of a seed field, axial magnetic fields in the 2000 T range may be achieved. A variety of concepts have been identified for the first experimental campaigns on Atlas. Experimental configurations, associated physics issues, and diagnostic strategies are all under investigation as the design of the Atlas facility proceeds. Near-term proof-of-principle experiments employing the smaller Pegasus II capacitor bank have been identified, and several of these experiments have now been performed. This paper discusses a number of recent Pegasus II experiments and identifies several areas of research presently planned on Atlas.
In a series of experiments using two-, four- and eight-beam 10.6 mu m laser irradiation of a variety of target (Ni, Cu) geometries, a significant amount of energy was found to be deposited in regions ...remote from the focal spots. The deposition patterns can be predicted with a self-generated magnetic field model.--AA
High-energy density experiments for Atlas Trainor, R.J.; Parsons, W.M.; Bartsch, R.R. ...
25th Anniversary, IEEE Conference Record - Abstracts. 1998 IEEE International Conference on Plasma Science (Cat. No.98CH36221),
1998
Conference Proceeding
Summary form only given, as follows. Atlas is a high-energy pulsed-power facility under development at Los Alamos National Laboratory to drive high-energy density experiments. It is optimized for ...materials properties and hydrodynamics experiments under extreme conditions. The system is designed to implode heavy liner loads with a peak current of 30-40 MA delivered in /spl sim/4 /spl mu/s. Atlas will be operational in near the end of 2000 and is designed to provide 100 shots per year. The Atlas capacitor bank consists of an array 240-kV Marx modules storing a total of 24-MJ. For many applications the Atlas liner will be a nominal 50-gram-aluminum cylinder with /spl sim/5-cm radius and 4-cm length. Implosion velocities up to 20 km/s are predicted. Using composite inner layers and a variety of interior target designs, a wide variety of experiments in /spl sim/cm/sup 3/ volumes may be performed. These include shock compression experiments up to /spl sim/2 TPa (20 Mbar), quasi-adiabatic compressions up to 6-fold compression and pressures above 10 TPa, hydrodynamic instability studies in nonlinear and turbulent regimes over multi-cm propagation lengths, experiments with dense, strongly-coupled plasmas, studies of materials response at very high strains and strain rates, and materials studies in ultrahigh magnetic fields (above 10/sup 3/ T). Experimental configurations, associated physics issues, and diagnostic strategies will be discussed. Near-term proof-of-principle experiments on the smaller Pegasus II capacitor bank will be identified.
Material science experiments on the Atlas facility Keinigs, R.K.; Atchison, W.L.; Anderson, W.E. ...
PPPS-2001 Pulsed Power Plasma Science 2001. 28th IEEE International Conference on Plasma Science and 13th IEEE International Pulsed Power Conference. Digest of Papers (Cat. No.01CH37251),
2001, Letnik:
1
Conference Proceeding
Odprti dostop
Three material properties experiments that are to be performed on the Atlas pulsed power facility are described; friction at sliding metal interfaces, spallation and damage in convergent geometry, ...and plastic flow at high strain and high strain rate. Construction of this facility has been completed and experiments in high energy density hydrodynamics and material dynamics will begin in 2001.
Using tamped exploding wires to generate strongly coupled plasmas Tierney, T.; Benage, J.; Evans, S. ...
IEEE Conference Record - Abstracts. PPPS-2001 Pulsed Power Plasma Science 2001. 28th IEEE International Conference on Plasma Science and 13th IEEE International Pulsed Power Conference (Cat. No.01CH37,
2001
Conference Proceeding
Summary form only given. Plasmas become strongly coupled (SCP) when the coulomb interaction energy between particles is comparable or greater than the thermal kinetic energy. This occurs at low ...temperatures (T/spl sim/1 eV) and high densities (n/sub c//spl sim/10/sup 21/ cm/sup -3/). SCPs are found in the interior of gas planets and white dwarf stars, as well as in high energy density physics experiments. We present a pulsed power and plasma shaping system designed to generate an aluminum SCP with a rectangular column profile. A 3.5 kJ, 4-stage Marx has been constructed to explode 200-micron aluminum wires fused in lead glass (/spl rho//spl sim/5.4 g/cm/sup 3/). The glass tamper restricts the exploding wires radial expansion, while axial expansion is permitted. The central region of the expanding plasma passes through a 100-micron square aperture assembly creating a plasma column. Above the aperture, the plasma plume is expected to have a density of one-tenth solid (/spl rho//spl sim/0.27 g/cm/sup 3/) and a temperature of the order I eV. Absorption of magnesium K-shell x-rays from a laser-produced backlighter is used to measure the density of the plasma. An optical pyrometer is used to estimate the plasma surface temperature based on a blackbody approximation with constant emissivity. Raven and Crunch were used to simulate the behavior inside the tamped region using conductivity tables generated by Desjarlais. The simulations predict fairly uniform density and temperature conditions in the central 100-microns of the tamped exploding wire. The plasma plume above the aperture will be used for equation of state studies of SCP matter.
Los Alamos National Laboratory is contributing to the core science and technology of the inertial confinement fusion program leading to the National Ignition Facility. Short summaries of a sample of ...recent experimental and related theoretical work are presented.
Excess photon detachment of negative hydrogen ions Zhao, X.M.; Gulley, M.; Bryant, H.C. ...
Summaries of Papers Presented at the Quantum Electronics and Laser Science Conference,
1996
Conference Proceeding
Summary form only given. Excess photon detachment (EPD) occurs when an electron is released from a negative ion with an energy corresponding to the absorption of more photons than the minimum number ...needed for detachment. We study the EPD of the simplest two-electron atom the negative hydrogen ion, with photons of energy 1.17 eV. Our time of flight (TOF) spectrum can be interpreted as an EPD spectrum with photoelectron peaks corresponding to single- and two-photon absorption.
Summary from only given. We present experimental time-resolved X-ray diffraction data that provide firm evidence that the response of single crystal silicon to nanosecond timescale uniaxial shock ...compression along the (400) axis is anomalous in that it is purely elastic.
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