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Laser-plasma interaction experiments at laser wavelengths of 1. 064. mu. m, 0. 532. mu. m, and 0. 355. mu. m

Description: The effect of laser wavelength on laser-plasma coupling is one of the critical issues facing the laser driven inertial confinement community. The advantages of using lasers with output wavelength less than 1 ..mu..m, such as enhanced absorption and hydrodynamic efficiency, reduction in parametric instabilities and corresponding suprathermal electron generation, have long been predicted theoretically.
Date: January 1, 1982
Creator: Campbell, E. M.; Mead, W. C. & Turner, R. E.
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Partner: UNT Libraries Government Documents Department
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Computation of self-consistent 2-D MHD with neutral-beam and bootstrap currents in elongated plasmas

Description: The observation of substantial current drive from neutral beam injection (NBI) in TFTR, JET and DIII-D has led to renewed interest in a steady state, non-inductively driven tokamak. The discovery of apparently considerable neoclassical (bootstrap) current in TFTR, makes a steady state device even more attractive since the bootstrap portion of the current could be obtained without additional power input. Motivated by these results, we have developed a code, ACCOME, which self-consistently comput… more
Date: April 5, 1983
Creator: Devoto, R. S.; Tani, K. & Azumi, M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Potential energy for quarks

Description: It is argued on theoretical and phenomenological grounds that confinement of quarks is intrinsically a many-body interaction. The Born-Oppenheimer approximation to the bag model is shown to give rise to a static potential energy that consists of a sum of two-body Coulomb terms and a many-body confining term. Following the success of this potential in heavy Q anti Q systems it is being applied to Q/sup 2/ anti Q/sup 2/. Preliminary calculations suggest that dimeson bound states with exotic flavo… more
Date: January 1, 1985
Creator: Heller, L.
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Partner: UNT Libraries Government Documents Department
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Measurements of the dependence of damage thresholds on laser wavelength, pulse duration and film thickness

Description: Results of three experiments will be described. We used 351-nm and 355-nm pulses with durations of 0.6, 1, 5 and 9 ns measure thresholds for a variety of anti-reflectance and high reflectance coatings. The functional form t/sup m/, with t the pulse duration, was used to scale fluence thresholds measured at 0.6 ns to those measured at 9.0 ns. Values of the coefficient m ranged from 0.10 to 0.51. The average value was 0.30. In the second experiment, we measured thresholds at 1064 nm, 527 nm and 3… more
Date: March 1, 1984
Creator: Rainer, F.; Vercimak, C.L.; Milam, D.; Carniglia, C.K. & Tuttle Hart, T.
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Partner: UNT Libraries Government Documents Department
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Potential for efficient frequency conversion at high average power using solid state nonlinear optical materials

Description: High-average-power frequency conversion using solid state nonlinear materials is discussed. Recent laboratory experience and new developments in design concepts show that current technology, a few tens of watts, may be extended by several orders of magnitude. For example, using KD*P, efficient doubling (>70%) of Nd:YAG at average powers approaching 100 KW is possible; and for doubling to the blue or ultraviolet regions, the average power may approach 1 MW. Configurations using segmented apertur… more
Date: October 28, 1985
Creator: Eimerl, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Current drive and heating systems based on high-energy (1- to 3-MeV) negative ion beams

Description: This paper describes a concept for a current drive system based on negative ions with beam energy > 1 MeV. Preliminary physics calculations show that the core current necessary for stability enhancement can best be achieved by beams with energy ranging from 1 to 4 MeV. Further study and experiments will better define the optimum energy. Work under way at Oak Ridge National Laboratory (ORNL) and at collaborating institutes in Canada and the Federal Republic of Germany is defining a system, its e… more
Date: January 1, 1988
Creator: Becraft, W. R.; Akerman, M. A.; Haselton, H. H.; Murphy, B. D.; Lousteau, D. C.; Ryan, P. M. et al.
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Partner: UNT Libraries Government Documents Department
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Methods of driving current by heating a toroidal plasma

Description: In addition to the usual mechanism which utilizes the Ohmic transformer current, which is necessarily pulsed, there exist several steady-state mechanisms. Heating mechanisms which can lend themselves efficiently to continuous current generation include neutral beams, Alfven waves, ion-cyclotron waves, lower-hybrid waves and electron-cyclotron waves.
Date: August 1, 1980
Creator: Fisch, N. J.
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Partner: UNT Libraries Government Documents Department
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Acceleration of beam ions during major radius compression in TFTR

Description: Tangentially co-injected deuterium beam ions were accelerated from 82 keV up to 150 keV during a major radius compression experiment in TFTR. The ion energy spectra and the variation in fusion yield were in good agreement with Fokker-Planck code simulations. In addition, the plasma rotation velocity was observed to rise during compression.
Date: September 1, 1985
Creator: Wong, K. L.; Bitter, M.; Hammett, G. W.; Heidbrink, W.; Hendel, H.; Kaita, R. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Recent progress on ATF

Description: The ATF experiment will test improvements to high-beta, steady-state toroidal confinement using external helical fields. The device design has been optimized to (1) provide direct access to the high-beta second-stability regime, (2) have sufficient flexibility to study a large range of toroidal configurations both with and without plasma current, (3) test the reduction of low-collisionality transport by EXB drifts induced by the self-consistent radial electric field, and (4) permit steady-state… more
Date: January 1, 1984
Creator: Neilson, G.H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Alignment and focusing device for a multibeam laser system

Description: Large inertial confinement fusion laser systems have many beams focusing on a small target. The Antares system is a 24-beam CO/sub 2/ pulse laser. To produce uniform illumination, the 24 beams must be individually focused on (or near) the target's surface in a symmetric pattern. To assess the quality of a given beam, we will locate a Smartt (point diffraction) interferometer at the desired focal point and illuminate it with an alignment laser. The resulting fringe pattern shows defocus, lateral… more
Date: January 1, 1980
Creator: Sweatt, W.C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Neoclassical transport in stellarators

Description: The stellarator neoclassical transport due to particles trapped in local helical wells is calculated in the low-collisionality regime using a systematic expansion. The behavior of electron transport is found to be the same over a wide range of energies, but the behavior of ion transport for low energy ions is found to be different than that for high energy ions. Furthermore, the electron fluxes do not vary with the change in the radial ambipolar electric field nearly as much as do the ion fluxe… more
Date: September 1, 1985
Creator: Ho, D.D.M. & Kulsrud, R.M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Shear alfven resonances in Tokapole II

Description: It has been suggested that efficient heating can occur by coupling energy through the shear Alfven resonance that is predicted to occur at particular locations within inhomogeneous plasmas. This heating mechanism should be applicable to tokamaks; however, the existence of the resonances in tokamaks has not yet been established experimentally. We present here direct observations of localized enhancement in the driven wave magnetic field which are compatible with theoretical predictions for the s… more
Date: March 1, 1982
Creator: Witherspoon, F.D.; Prager, S.C. & Sprott, J.C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Recent US target-physics-related research in heavy-ion inertial fusion: simulations for tamped targets and for disk experiments in accelerator test facilities

Description: Within the last few years, there have also appeared in the Heavy-Ion Fusion literature several studies of targets which have outer tampers. One-dimensional simulations indicate higher target gains with a judicious amount of tamping. But for these targets, a full investigation has not been carried through in regards to conservative criteria for fluid instabilities as well as reasonable imperfections in target fabrication and illumination symmetry which all affect target ignition and burn. Compar… more
Date: June 24, 1982
Creator: Mark, J.W.K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Use of ICRH for startup and initial heating of the TMX-U central cell

Description: Ion cyclotron resonance heating (ICRH) was evaluated and it was found to be satisfactory for use in establishing the conditions necessary to form a thermal barrier in TMX-upgrade (TMX-U). We discuss the constraints that must be satisfied in order to maintain a plasma, and outline a complete startup scenario that ends with the plasma at design parameters. The detailed discussions in this report concentrate on those parts of startup where ICRH is necessary. The ability of ICRH to couple power int… more
Date: May 1, 1982
Creator: Molvik, A.W. & Falabella, S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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High beta studies on ISX-B with neutral beam injection

Description: Injection of H/sup 0/ into D/sup +/ plasmas with beam power P/sub b/ of up to 1.7 MW has produced rms betas of approx. 4%, volume-averaged betas of approx. 3%, and central betas of approx. 10% in the ISX-B tokamak. Although theoretical calculations indicate that the observed equilibria may be unstable to ballooning modes, no catastrophic loss of confinement has been observed, and beta continues to increase with injection power. In these beam-dominated high-beta discharges the electron and ion e… more
Date: September 1980
Creator: Sheffield, J.; Bates, S.C. & Bush, C.E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Phoenix I energy extraction experiment

Description: Energy extraction experiments are reported for the Phoenix I amplifier driven by a discharge-initiated oscillator-preamplifier system operating on mixtures of either SF/sub 6/-HI or SF/sub 6/-C/sub 2/H/sub 6/ and an electron-beam-initiated intermediate amplifer (lambda-3) fueled with H/sub 2/ and F/sub 2/ mixtures. When the oscillator-preamplifier system operated with mixtures of SF/sub 6/-HI the input spectrum to the Phoenix I amplifier contained approx. 28 P-branch vibrational-rotational line… more
Date: July 1, 1980
Creator: Hoffman, J. M.; Patterson, E. L.; Tisone, G. C. & Moreno, J. B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Full-wave calculations in flux coordinates for toroidal geometry

Description: A new 2-D full-wave code, HYPERION, employing a poloidal and toroidal mode expansion and including the toroidal terms arising in the wave equation has been developed. It is based on the existing modules developed for the MHD stability codes and uses as input the tokamak equilibria calculated with the RSTEQ code. At present the plasma response is described by the collisionally broadened cold plasma conductivity. However, the code is written in straight field line coordinates, this permits the ac… more
Date: January 1, 1988
Creator: Carreras, B. A.; Lynch, V. E.; Jaeger, E. F. & Batchelor, D. B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Role of diagnostic testing in identifying and resolving dimensional-stability problems in electroplated laser mirrors

Description: The metal mirrors which are the subject of this discussion are to be used in the Antares inertial fusion laser system. Antares is a high-power (40 TW), high-energy (35 to 40 kJ), pulsed CO/sub 2/ laser system for the investigation of inertial confinement fusion. The system contains more than four hundred small and large diamond-turned and conventionally polished mirrors. The largest mirrors are trapezoidal in shape with the longest dimension being 16 to 18 inches. The substrates are type 2124 a… more
Date: January 1, 1982
Creator: Cutler, R.L. & Hogan, B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Three novel tokamak plasma regimes in TFTR

Description: Aside from extending ''standard'' ohmic and neutral beam heating studies to advanced plasma parameters, TFTR has encountered a number of special plasma regimes that have the potential to shed new light on the physics of tokamak confinement and the optimal design of future D-T facilities: (1) High-powered, neutral beam heating at low plasma densities can maintain a highly reactive hot-ion population (with quasi-steady-state beam fueling and current drive) in a tokamak configuration of modest bul… more
Date: October 1, 1985
Creator: Furth, H.P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Optical-scattering measurements from 1. 06-. mu. m, 0. 53-. mu. m, and 0. 35-. mu. m laser-heated disk targets

Description: A discussion is presented on scattered light measurements relevant to three of the important parametric instabilities which occur in high intensity laser plasma interactions: stimulated Brillouin scattering (SBS), the two plasmon decay instability (2-..omega../sub pe/), and stimulated Raman scattering (SRS). Most of these experiments were carried out on the ARGUS facility. Its configuration is described for the multiple wavelength experiments, all of which were conducted with one beam illuminat… more
Date: January 1, 1982
Creator: Turner, R. E.; Campbell, E. M.; Phillion, D. W.; Mead, W. C.; Ze, F.; Max, C. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Investigation on the damage threshold of films coated on various silicate, fluorophosphate and phosphate laser glasses. Final report, January 1, 1979-August 29, 1980

Description: Effects of substrate laser glass on the damage threshold and adhesion of dielectric films has been studied in order to improve the damage threshold. The study is divided into two parts: the first part dealing with four types of laser glass, LSG-91H silicate, LHG-8 phosphate, P-1 phosphate and LHG-10 fluorophosphate; the second part dealing with twenty-six glasses with systematically modified compositions in three glass systems, silicate, phosphate and fluorophosphate.
Date: January 1, 1980
Creator: Nakajima, Y & Izumitani, T
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Experimental development of nuclear pumped laser candidate inertial confinement fusion driver

Description: This progress report is submitted at the end of the first year of a 3-year project grant studying development of a nuclear pumped atomic iodine laser. The first section of the report will provide background on the study and briefly describe the original plans for the 3-year project. The second section will detail the work done to date. Included will be a description of the preparations made for experimentation, as well as some preliminary results recently obtained. Plans for the upcoming budget… more
Date: May 31, 1989
Creator: Miley, George H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Fuel temperature determination for ICF microspheres

Description: The common heuristic expression for estimating thermonuclear burn in ICF microspheres far from bootstrap heating is often used for inversion to obtain peak temperatures from experimental data. It contains an ad hoc or fitted parameter and lacks some parameters of obvious influence in actual systems. We present an alternative expression, which may be usefully inverted and does not suffer these defects.
Date: August 1, 1980
Creator: Henderson, D.B. & Giovanielli, D.V.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Energy and technology review

Description: The state of the laboratory address by LLNL Director Roger Batzel is summarized, and a breakdown of the laboratory funding is given. The Livermore defense-related committment is described, including the design and development of advanced nuclear weapons as well as research in inertial confinement fusion, nonnuclear ordnance, and particle beam technology. LLNL is also applying its scientific and engineering resources to the dual challenge of meeting future energy needs without degrading the qual… more
Date: July 1, 1982
Creator: Stowers, I.F.; Crawford, R.B.; Esser, M.A.; Lien, P.L.; O'Neal, E. & Van Dyke, P. (eds.)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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