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Simultaneously time- and space-resolved spectroscopic characterization of laser-produced plasmas

Description: The CHROMA laser facility at KMS Fusion has been used to irradiate a variety of microdot targets. These include aluminum dots and mixed bromine dots doped with K-shell (magnesium) emitters. Simultaneously time- and space-resolved K-shell and L-shell spectra have been measured and compared to dynamic model predictions. The electron density profiles are measured using holographic interferometry. Temperatures, densities, and ionization distributions are determined using K-shell and L-shell spectra… more
Date: March 3, 1988
Creator: Charatis, G.; Young, B. K. F.; Busch, G. E.; Cerjan, C. J.; Goldstein, W. H.; Osterheld, A. L. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Software Engineering Processes Used to Develop the NIF Integrated Computer Control System

Description: We have developed a new target platform to study Laser Plasma Interaction in ignition-relevant condition at the Omega laser facility (LLE/Rochester)[1]. By shooting an interaction beam along the axis of a gas-filled hohlraum heated by up to 17 kJ of heater beam energy, we were able to create a millimeter-scale underdense uniform plasma at electron temperatures above 3 keV. Extensive Thomson scattering measurements allowed us to benchmark our hydrodynamic simulations performed with HYDRA [1]. As… more
Date: October 3, 2007
Creator: Ludwigsen, A P; Carey, R W; Demaret, R D; Lagin, L J; Reddi, U P & Van Arsdall, P J
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Final Technical Report, DOE Grant DE-FG02-98ER54496, Physics of High-Energy-Density X Pinch Plasmas

Description: Abstract for the Final Technical Report, DOE Grant DE-FG02-98ER54496 An X-pinch plasma is produced by driving a high current (100-500 kiloamperes) through two or more fine wires that cross and touch at a point, forming an X in the case of two wires. The wires explode because of the high current, and then the resulting plasma is imploded radially inward by the magnetic field from the current. When the imploding material briefly stagnates at very small radius and high density, an intense burst of… more
Date: December 3, 2008
Creator: Hammer, David
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Uv Thomson scattering from x-ray laser plasmas

Description: Plasmas produced by irradiating massive carbon targets with a 1.064 {mu}m, 1.5 ns laser pulse at incident energies of {approximately}100 J have been investigated. UV thermal Thomson scattering was used to obtain the electron and ion temperatures, as well as drift velocities. The electron density was obtained by optical interferometry. The results are compared to hydrodynamic computer modeling. 6 refs., 6 figs.
Date: January 3, 1991
Creator: La Fontaine, B.; Baldis, H. A.; Villeneuve, D. M.; Bernard, J. E.; Enright, G. D. (National Research Council of Canada, Ottawa, ON (Canada)); Rosen, M. D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Modification Of The Electron Energy Distribution Function During Lithium Experiments On The National Spherical Torus Experiment

Description: The National Spherical Torus Experiment (NSTX) has recently studied the use of a liquid lithium divertor (LLD). Divertor Langmuir probes have also been installed for making measurements of the local plasma conditions. A non-local probe interpretation method is used to supplement the classical probe interpretation and obtain measurements of the electron energy distribution function (EEDF) which show the occurrence of a hot-electron component. Analysis is made of two discharges within a sequence … more
Date: June 3, 2011
Creator: Jaworski, M. A.; Gray, T. K.; Kaita, R.; Kallman, J.; Kugel, H.; LeBlanc, B. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Predictions of H-mode performance in ITER

Description: Time-dependent integrated predictive modeling is carried out using the PTRANSP code to predict fusion power and parameters such as alpha particle density and pressure in ITER H-mode plasmas. Auxiliary heating by negative ion neutral beam injection and ion cyclotron heating of He3 minority ions are modeled, and the GLF23 transport model is used in the prediction of the evolution of plasma temperature profiles. Effects of beam steering, beam torque, plasma rotation, beam current drive, pedestal t… more
Date: March 3, 2008
Creator: R.V. Budny, R.Andre, G.Bateman, F.Halpern, C.E.Kessel, A.Kritz, and D.McCune
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Recent Liquid Lithium Limiter Experiments in CDX-U

Description: Recent experiments in the Current Drive eXperiment-Upgrade (CDX-U) provide a first-ever test of large area liquid lithium surfaces as a tokamak first wall, to gain engineering experience with a liquid metal first wall, and to investigate whether very low recycling plasma regimes can be accessed with lithium walls. The CDX-U is a compact (R=34 cm, a=22 cm, B{sub toroidal} = 2 kG, I{sub P} =100 kA, T{sub e}(0) {approx} 100 eV, n{sub e}(0) {approx} 5 x 10{sup 19} m{sup -3}) spherical torus at the … more
Date: May 3, 2005
Creator: Majeski, R.; Jardin, S.; Kaita, R.; Gray, T.; Marfuta, P.; Spaleta, J. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Operational Regimes of the National Spherical Torus Experiment

Description: The National Spherical Torus Experiment (NSTX) is a proof-of-principle experiment designed to study the physics of Spherical Tori (ST), i.e., low-aspect-ratio toroidal plasmas. Important issues for ST research are whether the high-eta stability and reduced transport theoretically predicted for this configuration can be realized experimentally. In NSTX, the commissioning of a digital real-time plasma control system, the provision of flexible heating systems, and the application of wall condition… more
Date: June 3, 2002
Creator: Mueller, D.; Bell, M. G.; Bell, R. E.; Bitter, M.; Bigelow, T.; Bonoli, P. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Turbulence in the Divertor Region of Tokamak Edge Plasma

Description: Results of recent modeling of tokamak edge plasma with the turbulence code BOUT are presented. In previous studies with BOUT the background profiles of plasma density and temperature were set as flux surface functions. However in the divertor region of a tokamak the temperature is typically lower and density is higher than those at the mid-plane. To account for this in the present study a poloidal variation of background plasma density and temperature is included to provide a more realistic mod… more
Date: September 3, 2003
Creator: Umansky, M V; Rognlien, T D; Xu, X Q; Cohen, R H & Nevins, W M
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Instability Driven by Sheath Boundary Conditions and Limited to Divertor Legs

Description: An instability driven by an electron temperature gradient in combination with sheath boundary conditions at a divertor plate is considered. It is shown that there exists a mode localized between the divertor plate and the x point. Further propagation of the mode is terminated by a strong shear near the x point. A ''heuristic'' boundary condition at the control surface situated somewhat below the x point is suggested. The mode manifests a strong dependence on the radial tilt of the divertor plat… more
Date: September 3, 2003
Creator: Ryutov, D. D. & Cohen, R. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Detailed Hydrodynamic and X-Ray Spectroscopic Analysis of a Laser-Produced Rapidly-Expanding Aluminum Plasma

Description: We present a detailed analysis of K-shell emission from laser-produced rapidly-expanding aluminum plasmas. This work forms part of a series of experiments performed at the Vulcan laser facility of the Rutherford Appleton Laboratory, UK. 1-D planar expansion was obtained by over-illuminating Al-microdot targets supported on CH plastic foils. The small size of the Al-plasma ensured high spatial and frequency resolution of the spectra, obtained with a single crystal spectrometer, two vertical disp… more
Date: April 3, 2001
Creator: Chambers, D M; Glenzer, S H; Hawreliak, J; Wolfrum, E; Gouveia, A; Lee, R W et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Physics of Neutralization of Intense Charged Particle Beam Pulses by a Background Plasma

Description: Neutralization and focusing of intense charged particle beam pulses by a background plasma forms the basis for a wide range of applications to high energy accelerators and colliders, heavy ion fusion, and astrophysics. For example, for ballistic propagation of intense ion beam pulses, background plasma can be used to effectively neutralize the beam charge and current, so that the self-electric and self-magnetic fields do not affect the ballistic propagation of the beam. From the practical persp… more
Date: September 3, 2009
Creator: Kaganovich, I. D.; Davidson, R. C.; Dorf, M. A.; Startsev, E. A.; Sefkow, A. B.; Friedman, A. F. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The dynamics of core temperature fluctuations during sawtooth oscillations on TEXT-U

Description: Core electron temperature fluctuations are measured in a tokamak plasma where some degree of time resolution is achieved. There is a strong correlation between the turbulence level and the phase of the sawtooth oscillation. A global linear relationship between the temperature fluctuation amplitude and the electron temperature gradient scale length is found. The enhancement in fluctuations at the sawtooth crash is correlated to a steepening of the electron temperature gradient created as the saw… more
Date: May 3, 1995
Creator: Watts, C. & Gandy, R.F.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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