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Plasma confinement experiments in the TMX tandem mirror. Paper IAEA-CN-38/F-1

Description: Results from the new Tandem Mirror Experiment (TMX) are described. Tandem-mirror density and potential profiles are produced using end-plug neutral-beam injection and central-cell gas-fueling. TMX parameters are near those predicted theoretically. The end-plug electron temperature is higher than in the comparably sized single-mirror 2XIIB. Axial confinement of the finite-beta central-cell plasma is improved by the end plugs by as much as a factor of 9. In TMX, end-plug microinstability limits c… more
Date: May 22, 1980
Creator: Simonen, T. C.; Anderson, C. A. & Casper, T. A.
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Partner: UNT Libraries Government Documents Department
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12.6 keV Kr K-alpha X-ray Source For High Energy Density Physics Experiments

Description: A high contrast 12.6 keV Kr K{alpha} source has been demonstrated on the petawatt-class Titan laser facility. The contrast ratio (K{alpha} to continuum) is 65, with a competitive ultra short pulse laser to x-ray conversion efficiency of 10{sup -5}. Filtered shadowgraphy indicates that the Kr K{alpha} and K{beta} x-rays are emitted from a roughly 1 x 2 mm emission volume, making this source suitable for area backlighting and scattering. Spectral calculations indicate a typical bulk electron temp… more
Date: April 22, 2008
Creator: Kugland, N.; Constantin, C. G.; Niemann, C.; Neumayer, P.; Chung, H.; Doppner, T. et al.
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Partner: UNT Libraries Government Documents Department
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MFTF-B electron-cyclotron-resonance heating system

Description: The MFTF-B ECRH system will provide 1.6-MW of microwave power for heating of electrons within the thermal barrier and potential maximum regions of the plasma end-plugs. Absorption of this radiation increases the resonant electron energy which locally alters the electrostatic confining potential within the plasma. The result is a thermal barrier which will isolate end-plug electrons from those in the solenoid thus increasing the plasma confinement time. Microwave energy will be generated by eigh… more
Date: October 22, 1981
Creator: Krause, K. H.; Pollock, G. G. & Yugo, J. J.
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Partner: UNT Libraries Government Documents Department
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DSP: A detailed spectroscopy postprocessor for H-, He-, and Li-like ions

Description: A detailed plasma spectroscopy postprocessor for H-, He-, and Li-like ions with 6 {le} Z {le} 26 has been constructed. The structure of the code and the physics contained within it will be described and a sample application given. 15 refs., 5 figs.
Date: February 22, 1991
Creator: Keane, C.J.; Lee, R.S. (Lawrence Livermore National Lab., CA (USA)) & Grandy, J.P. (Massachusetts Inst. of Tech., Cambridge, MA (USA))
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Partner: UNT Libraries Government Documents Department
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Observations of parametric instabilities in long-scalelength plasmas

Description: This paper is organized in the following manner. In the second section we discussed absorption; the dependence of scattered light signatures of parametric instabilities occurring at n/sub e/ less than or equal to n/sub c//4 on corona size is shown in section three; and evidence for suprathermal electron production in these long-scale length plasmas is presented in section four. The results and conclusions are finally summarized in section five.
Date: March 22, 1983
Creator: Campbell, E. M.; Max, C. E.; Phillion, D. W.; Turner, R. E.; Estabrooke, K.; Laskinski, B. et al.
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Partner: UNT Libraries Government Documents Department
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Characterizing Electron Temperature Gradient Turbulence Via Numerical Simulation

Description: Numerical simulations of electron temperature gradient (ETG) turbulence are presented which characterize the ETG fluctuation spectrum, establish limits to the validity of the adiabatic ion model often employed in studying ETG turbulence, and support the tentative conclusion that plasmaoperating regimes exist in which ETG turbulence produces sufficient electron heat transport to be experimentally relevant. We resolve prior controversies regarding simulation techniques and convergence by benchmar… more
Date: May 22, 2006
Creator: Nevins, W M; Candy, J; Cowley, S; Dannert, T; Dimits, A; Dorland, W et al.
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Partner: UNT Libraries Government Documents Department
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Nonlinear Turbulence Simulations for NSTX H-modes

Description: Present evidence points to remarkably resilient electron temperature profiles in high-density H-mode plasmas on the National Spherical Torus Experiment (NSTX), suggesting that the underlying electron thermal transport mechanisms respond in a highly nonlinear fashion to changes in the gradients. This paper uses measured plasma profiles as input to linear gyrokinetic analysis to identify candidate micro-instabilities that may be responsible for the electron thermal transport. The criteria for use… more
Date: June 22, 2004
Creator: Redi, M. H.; Kaye, S.; Dorland, W.; Bell, R.; Bourdelle, C.; Ethier, S. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Supersonic Propagation of Ionization Waves in an Under-Dense, Laser-Produced Plasma

Description: We observe a laser-driven supersonic ionization wave heating a mm-scale plasma of sub-critical density up to 2-3 keV electron temperatures. Propagation velocities initially 10 times the sound speed were measured by means of time-resolved x-ray imaging diagnostics. The measured ionization wave trajectory is modeled analytically and by a 2D radiation-hydrodynamics code. The comparison to the modeling suggests that nonlocal heat transport effects may contribute to the attenuation of the heat wave … more
Date: October 22, 2004
Creator: Constantin, C.; Back, C. A.; Fournier, K. B.; Gregori, G.; Landen, O. L.; Glenzer, S. H. et al.
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Partner: UNT Libraries Government Documents Department
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Thomson Scattering From Inertial Confinement Fusion Targets

Description: We have applied ultraviolet Thomson scattering to accurately measure the electron and ion temperature in high-density gas-filled hohlraums at the Nova laser facility. The implementation of a short-wavelength probe laser that operates at 263 nm (4{omega}) has allowed us for the first time to investigate scalings to high gas fill densities and to characterize the hohlraum conditions of the low-Z gas plasma. as well as of the high-Z wall plasma. These measurements have provided us with a unique da… more
Date: July 22, 1999
Creator: Baldis, H. A.; Estabrook, K. G.; Glenzer, S. H. & Suter, L. J.
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Partner: UNT Libraries Government Documents Department
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Analysis and interpretation of a high density tandem negative ion source

Description: In the last few years the development of tandem-discharge hydrogen-negative-ion-source systems has proceeded along both experimental and theoretical lines. To some extent these developments have proceeded independently, either the available theoretical model was inadequate to account for a specific geometrical configuration, or the experimental data was not sufficient to provide adequate input parameters for calculation. In the tandem system described here the electron temperature, electron den… more
Date: October 22, 1986
Creator: Hiskes, J.R.; Lietzke, A.F. & Hauck, C.
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Partner: UNT Libraries Government Documents Department
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Orbit averaged radial buildup code for tandem mirror geometry

Description: The radial Fokker-Planck (RFP) model of A. Futch was modified to treat plasma buildup in the tandem mirror plug and center cell with a self-consistent model (TOARBUC). Two major changes have been made to the original version of this code. First, the center cell is treated as having separate electron and ion confining potentials with the ion potential having the opposite sign of that in a conventional mirror. Second, a two-electron-temperature treatment derived by R. Cohen was included in the pr… more
Date: January 22, 1981
Creator: Campbell, M. & Futch, A.H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Recent experimental progress in the TMX-U thermal barrier tandem mirror experiment

Description: Recent experiments on the TMX-U thermal barrier device at LLNL have achieved the end plugging of axial ion losses up to a central cell density of n/sub c/ = 2 x 10/sup 12/ cm. During these tests, the axial potential profile characteristic of a thermal barrier has been measured experimentally, indicating an ion-confining potential greater than 1.5 kV and a potential depression of 0.45 kV in the barrier region. The average beta of hot electrons in the thermal barrier has been increased to 15% and… more
Date: June 22, 1984
Creator: Turner, W. C.; Allen, S. L.; Casper, T. A.; Clauser, J. F.; Coensgen, F. H.; Correll, D. L. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Measurement of Heat Propagation in a Laser Produced Plasma

Description: We present the observation of a nonlocal heat wave by measuring spatially and temporally resolved electron temperature profiles in a laser produced nitrogen plasma. Absolutely calibrated measurements have been performed by resolving the ion-acoustic wave spectra across the plasma volume with Thomson scattering. We find that the experimental electron temperature profiles disagree with flux-limited models, but are consistent with transport models that account for the nonlocal effects in heat cond… more
Date: August 22, 2003
Creator: Gregori, G.; Glenzer, S. H.; Knight, J.; Niemann, C.; Price, D.; Froula, D. H. et al.
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Partner: UNT Libraries Government Documents Department
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Thermal Effects in Intense Laser-Plasma Interactions

Description: We present an overview of a new warm fluid model that incorporates leading-order kinetic corrections to the cold fluid model without making any near-equilibrium assumptions. In the quasi-static limit we obtain analytical expressions for the momentum spread and show excellent agreement with solutions of the full time-dependant equations. It is shown that over a large range of initial plasma temperatures, the fields are relatively insensitive to the pressure force. We discuss implications of this… more
Date: October 22, 2004
Creator: Shadwick, B. A.; Tarkenton, G. M. & Esarey, E. H.
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Partner: UNT Libraries Government Documents Department
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