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Universal formula for the quasistatic second-order density perturbation by a cold magnetoplasma wave

Description: Using the general expression for the ponderomotive Hamiltonian, the quasi-static quasi-neutral density change caused by the ponderomotive force of a cold magnetoplasma wave of arbitrary frequency and polarization is obtained. This formula agrees with and extends previous results for unmagnetized and magnetized plasma.
Date: December 16, 1977
Creator: Kaufman, A. N.; Cary, J. R. & Pereira, N. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Calculation of density profiles in tandem mirrors fueled by pellets

Description: We have modified the LLNL radial transport code TMT to model reactor regime plasmas, fueled by pellets. The source profiles arising from pellet fueling are obtained from existing pellet ablation models. Because inward radial diffusion due to inverted profiles must compete with trapping of central cell ions in the transition region for tandem mirrors, pellets must penetrate fairly far into the plasma. In fact, based on our radial calculations, a pellet with a velocity of 10 km/sec cannot sustain… more
Date: December 2, 1983
Creator: Campbell, R. B. & Gilmore, J. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Initial results from the scoop limiter experiment in PDX

Description: A particle scoop limiter with a graphite face backed by a 50 liter volume for collecting particles was used in PDX. Experiments were performed to test its particle control and power handling capabilities with up to 5 MW of D/sup 0/ power injected into D/sup +/ plasmas. Line average plasma densities up to 8 x 10/sup 13/ cm/sup -3/ and currents up to 450 kA were obtained. Plasma densities in the scoop channels greater than 2 x 10/sup 13/ cm/sup -3/ and neutral densities in the scoop volume greate… more
Date: December 1, 1983
Creator: Budny, R.; Bell, M.; Bol, K.; Boyd, D.; Buchenauer, D.; Cavallo, A. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Control of Laser Plasma Based Accelerators up to 1 GeV

Description: This dissertation documents the development of a broadband electron spectrometer (ESM) for GeV class Laser Wakefield Accelerators (LWFA), the production of high quality GeV electron beams (e-beams) for the first time in a LWFA by using a capillary discharge guide (CDG), and a statistical analysis of CDG-LWFAs. An ESM specialized for CDG-LWFAs with an unprecedented wide momentum acceptance, from 0.01 to 1.1 GeV in a single shot, has been developed. Simultaneous measurement of e-beam spectra and … more
Date: December 3, 2007
Creator: Nakamura, Kei
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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Plasma density gradient injection of low absolute momentum spread electron bunches

Description: Plasma density gradients in a gas jet were used to control the wake phase velocity and trapping threshold in a laser wakefield accelerator, producing stable electron bunches with longitudinal and transverse momentum spreads more than ten times lower than in previous experiments (0.17 and 0.02 MeV/c FWHM, respectively) and with central momenta of 0.76 +- 0.02 MeV/c. Transition radiation measurements combined with simulations indicated that the bunches can be used as a wakefield accelerator injec… more
Date: December 22, 2007
Creator: Geddes, C. G. R.; Nakamura, K.; Plateau, G. R.; Toth, Cs.; Cormier-Michel, E.; Esarey, E. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Edge Localized Mode Dynamics and Transport in the Scrape-Off Layer of the DIII-D Tokamak

Description: High temporal and spatial resolution measurements in the boundary of the DIII-D tokamak show that edge localized modes (ELMs) are produced in the low field side, are poloidally localized and are composed of fast bursts ({approx}20 to 40 {micro}s long) of hot, dense plasma on a background of less dense, colder plasma ({approx}5 x 10{sup 18} m{sup {+-}3}, 50 eV) possibly created by the bursts themselves. The ELMs travel radially in the scrapeoff layer (SOL), starting at the separatrix at {approx}… more
Date: December 3, 2004
Creator: Boedo, J. A.; Rudakov, D. L.; Hollmann, E.; Gray, D. S.; Burrell, K. H.; Moyer, R. A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Neutral-fueling pressure measurements and modeling near the plasma edge in TMX-U

Description: Large variations in pressure from external gas-fueling sources and from plasma-induced wall reflux along the TMX-U plasma have been observed. These pressure variations can produce locally high neutral density in the plasma, which strongly affects the plasma parameters. These local pressure measurements include data from a newly installed neutral-pressure diagnostic system of fast magnetron gauges. The plasma-induced warm-wall reflux has been observed to be primarily HD and H/sub 2/ as opposed t… more
Date: December 3, 1984
Creator: Pickles, W.L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Neutral-fueling pressure measurements and modeling near the plasma edge in TMX-U. Revision 1

Description: Large variations in pressure from external gas-fueling sources and from plasma-induced wall reflux along the TMX-U plasma have been observed. These pressure variations can produce locally high neutral density in the plasma, which strongly affects the plasma parameters. These local pressure measurements include data from a newly installed neutral-pressure diagnostic system of fast magnetron gauges. The plasma-induced warm-wall reflux has been observed to be primarily HD and H/sub 2/ as opposed t… more
Date: December 3, 1984
Creator: Pickles, W.L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Simulations of DT experiments in TFTR

Description: A transport code (TRANSP) is used to simulate future deuterium-tritium experiments (DT) in TFTR. The simulations are derived from 14 TFTR DD discharges, and the modeling of one supershot is discussed in detail to indicate the degree of accuracy of the TRANSP modeling. Fusion energy yields and {alpha}-particle parameters are calculated, including profiles of the {alpha} slowing down time, average energy, and of the Alfven speed and frequency. Two types of simulations are discussed. The main emph… more
Date: December 1, 1991
Creator: Budny, R.; Bell, M. G.; Biglari, H.; Bitter, M.; Bush, C.; Cheng, C. Z. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Parasitic excitation of ion Bernstein waves from a Faraday shielded fast wave loop antenna

Description: Parasitic excitation of ion Bernstein waves is observed from a Faraday shielded fast wave loop antenna in the ion cyclotron frequency range. Local analysis of the Vlasov-Maxwell equations demonstrates the role of plasma density gradient in the coupling process. The effects of plasma density and of parallel wave number on the excitation process are investigated.
Date: December 1, 1984
Creator: Skiff, F.; Ono, M.; Colestock, P. & Wong, K. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Atomic processes in high-density plasmas

Description: This review covers dense atomic plasmas such as that produced in inertial confinement fusion. The target implosion physics along with the associated atomic physics, i.e., free electron collision phenomena, electron states I, electron states II, and nonequilibrium plasma states are described. (MOW)
Date: December 21, 1982
Creator: More, R.M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Microspot target development with seeded and patterned plasma polymers

Description: A new class of targets for laser fusion experiments was fabricated using plasma-deposition and etching technology. Plasma polymer coatings seeded with silicon or sulfur were deposited as 300..mu..m diameter microspots inside holes of equal diameter in a pure hydrocarbon polymer film. The target was designed to study large-scale plasma instabilities and measure the temperature and density histories of laser induced plasmas. The microspot target required three new development: freestanding stress… more
Date: December 10, 1984
Creator: Letts, S. A.; Miller, D. E.; Corley, R. A.; Tillotson, T. M. & Witt, L. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Microwave reflectometry for the study of density fluctuations in tokamak plasmas

Description: The effect of small scale density fluctuations on the propagation of electromagnetic waves in an inhomogeneous magnetized plasma in the presence of a cutoff is investigated. It is shown that, provided the fluctuation scale length is greater than the free space wavelength of an incident plane wave, the scattered field is strongly enhanced from fluctuations near the turning point. Numerical results for wave propagation in a tokamak plasma demonstrate the feasibility of reflectometry for the local… more
Date: December 1, 1990
Creator: Mazzucato, E. & Nazikian, R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Magnetized target fusion: An ultra high energy approach in an unexplored parameter space

Description: Magnetized target fusion is a concept that may lead to practical fusion applications in a variety of settings. However, the crucial first step is to demonstrate that it works as advertised. Among the possibilities for doing this is an ultrahigh energy approach to magnetized target fusion, one powered by explosive pulsed power generators that have become available for application to thermonuclear fusion research. In a collaborative effort between Los Alamos and the All-Russian Scientific Institu… more
Date: December 31, 1994
Creator: Lindemuth, I. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Comparison of measured electron density rise and calculated neutral beam particle deposition in the TFTR tokamak

Description: The initial rate of rise of the central electron density during {approximately}100 keV deuterium neutral beam injection is found to agree well with calculations of the beam deposition rate. The best agreement is with beam deposition calculations using older tabulations of the atomic cross-sections; the effects of using new tabulations or including multi-step ionization processes appear to approximately cancel. The neutral-beam deposition profile is a strong function of both the magnitude and th… more
Date: December 1, 1991
Creator: Park, H.; Budny, R.; McCune, D.; Taylor, G.; Zarnstorff, M. C. & Barnes, C. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A New Diagnostic Technique to Simultaneously Measure the Electron Temperature, Ionic Charge State, and Plasma Density Near the Critical Surface in Laser-Plasma Interaction Experiments. Final Report

Description: We have studied the dependence of the second harmonic signature of the ion acoustic decay instability on the target material in laser produced plasmas. Well-defined Stokes peaks were observed. The Stokes peaks were especially sharp for high Z targets. The threshold of the IADI was quite low even in high Z plasma. It increased only weakly with increasing the atomic number. On the other hand, the Stokes intensity decreased strongly with increasing atomic number. Linear theory, combined with the r… more
Date: December 31, 1990
Creator: Mizuno, K.; DeGroot, J. S.; Seka, W. & Drake, R. P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Multichannel wave interferometry

Description: The analysis of multichannel wave interferometry for a variety of density profiles reveals that the phase shift as a function of horn position normalized to that through the center of the plasma, is relatively insensitive to K = n/sub o//n/sub c/ (the ratio of maximum density to cutoff density) when refraction effects are minimized. Thus, this ratio may be easily inverted to obtain a reasonably accurate measurement of the density profile even for values of K approaching 1.
Date: December 1, 1975
Creator: Hosea, J. C. & Jobes, F. C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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4th Generation ECR Ion Sources

Description: The concepts and technical challenges related to developing a 4th generation ECR ion source with an RF frequency greater than 40 GHz and magnetic confinement fields greater than twice Becr will be explored in this paper. Based on the semi-empirical frequency scaling of ECR plasma density with the square of operating frequency, there should be significant gains in performance over current 3rd generation ECR ion sources, which operate at RF frequencies between 20 and 30 GHz. While the 3rd generat… more
Date: December 1, 2008
Creator: Lyneis, Claude M.; Leitner, D.; Todd, D.S.; Sabbi, G.; Prestemon, S.; Caspi, S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Analytical and Numerical Ray Tracing of X-Ray Lasers

Description: Soft x-ray lasers in 10-30nm range are now routinely produced in hot plasmas generated either by a laser from a solid target or by an electrical discharge in a capillary. Such an x-ray laser is a convenient tool for future applications, such as probing dense plasmas of interest for fusion experiments. Their short wavelength enables plasma diagnosis beyond the capabilities of optical lasers, because the high critical plasma density ({approx}{lambda}{sup 2}) limits the optical beam propagation. I… more
Date: December 22, 2003
Creator: Kuba, J; Shlyaptsev, V N; Benredjem, D & Moller, C
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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ITER Experts' meeting on density limits

Description: The necessity of achieving a prescribed wall load or fusion power essentially determines the plasma pressure in a device like ITER. The range of operation densities and temperatures compatible with this condition is constrained by the problems of power exhaust and the disruptive density limit. The maximum allowable heat loads on the divertor plates and the maximum allowable sheath edge temperature practically impose a lower limit on the operating densities, whereas the disruptive density limit … more
Date: December 1, 1989
Creator: Borrass, K.; Igitkhanov, Y.L. & Uckan, N.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Simulations of DT experiments in TFTR

Description: A transport code (TRANSP) is used to simulate future deuterium-tritium experiments (DT) in TFTR. The simulations are derived from 14 TFTR DD discharges, and the modeling of one supershot is discussed in detail to indicate the degree of accuracy of the TRANSP modeling. Fusion energy yields and {alpha}-particle parameters are calculated, including profiles of the {alpha} slowing down time, average energy, and of the Alfven speed and frequency. Two types of simulations are discussed. The main emph… more
Date: December 1, 1991
Creator: Budny, R.; Bell, M. G.; Biglari, H.; Bitter, M.; Bush, C.; Cheng, C. Z. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Tritium transport, influx, and helium ash measurements on TFTR during DT operation

Description: The evolution of the tritium density profile is inferred from 14.1 MeV t(d,n){alpha} and 2.5 MeV d(d,n){sup 3}He neutron emissivity profiles measured in a deuterium neutral beam heated plasma into which a small amount of tritium gas has been puffed. For the first time, hydrogenic ion transport coefficients in the form of a diffusivity and convective velocity are determined. The particle diffusivities of tritium and {sup 4}He, and the deuterium thermal diffusivity are of similar magnitudes, and … more
Date: December 1, 1994
Creator: Efthimion, P. C.; Johnson, L. C. & Skinner, C. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Radiative Power Loss Calculations for Krypton and Argon in Intermediate-to-High Density Plasmas

Description: The scope of work for this subcontract requires that state-of-the-art, detailed atomic kinetics calculations be applied to compute the total radiative cooling rates for Ar and Kr in high density plasmas. This is in support of the Defense Threat Reduction Agency's program of development of simulators with high-fluence radiation and spectral fidelity. Using collisional-radiative modeling codes and unique expertise at Lawrence Livermore National Laboratory (LLNL), the total radiative yields from A… more
Date: December 1, 2001
Creator: Fournier, K B; Chung, H-K & Lee, R W
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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