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Fast Particle Destabilization of Toroidicity Induced Alfven Eigenmodes in National Spherical Torus Experiment

Description: Toroidicity induced Alfven Eigenmode (TAE) stability in National Spherical Torus Experiment (NSTX) is analyzed using the improved NOVA-K code, which includes finite orbit width and Larmor radius effects and is able to predicts the saturation amplitude for the mode using the quasilinear theory. Broad spectrum of unstable global TAEs with different toroidal mode numbers is predicted. Due to the strong poloidal field and the presence of the magnetic well in NSTX better particle confinement in the … more
Date: December 10, 1999
Creator: Cheng, C. Z.; Fu, G. Y.; Gorelenkova, M. V.; Gorelenkov, N. N.; White, R. & Kaye, S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Observation of Secondary Plasma Waves in Laser-Plasma Interaction Experiments

Description: An experiment is described where the two products of the Langmuir Decay Instability (LDI) of a primary electron plasma wave have been observed and identified without any ambiguity. Primary Langmuir waves are driven by Stimulated Raman Scattering (SRS) of an incident laser which provides well-defined electron plasma waves. Thomson scattering of a short wavelength probe beam yields measurements of the amplitude of the waves resolved in time, space, wavelength and wavevector, that allow identifica… more
Date: December 8, 1999
Creator: Depierreux, S.; Labaune, C.; Baldis, H. A.; Fuchs, J. & Michard, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Amplitude path corrections for regional phases in China

Description: The authors investigate the effectiveness of amplitude path corrections for regional phases on seismic event discrimination and magnitude estimation. Waveform data from digital stations in China for regional, shallow (< 50 km) events were obtained from the IRIS Data Management Center (DMC) for years 1986 to 1996 using the USGS Preliminary Determination of Epicenters (PDE) and the Chinese State Seismological Bureau (SSB) catalogs. For each event, the amplitudes for each regional phase (P{sub n},… more
Date: December 31, 1998
Creator: Phillips, W. S.; Velasco, A. A.; Taylor, S. R. & Randall, G. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Infrasonic observation of earthquakes

Description: Infrasound signals generated by earthquakes have been detected at arrays operated by the Los Alamos National Laboratory. Three modes of propagation are possible and all have been observed by the authors. The observations suggest that regions remote from the epicenters are excited and may serve as secondary source regions. A relation is found between the normalized peak amplitudes and the seismic magnitudes.
Date: December 31, 1998
Creator: Mutschlecner, J.P. & Whitaker, R.W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Infrasound from the El Paso super-bolide of October 9, 1997

Description: During the noon hour on October 9, 1997 an extremely bright fireball ({approx}-21.5 in stellar magnitude putting it into the class of a super-bolide) was observed over western Texas with visual sightings from as far away as Arizona to northern Mexico and even in northern New Mexico over 300 miles away. This event produced tremendously loud sonic boom reports in the El Paso area. It was also detected locally by 4 seismometers which are part of a network of 5 seismic stations operated by the Univ… more
Date: December 31, 1998
Creator: ReVelle, D. O.; Whitaker, R. W. & Armstrong, W. T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Phase synchronization of multiple klystrons in RF system

Description: The Low Energy Demonstration Accelerator (LEDA) being constructed at Los Alamos National Laboratory will serve as the prototype for the low energy section of the Acceleration Production of Tritium (APT) accelerator. The first LEDA RF system includes three, 1.2 MW, 350 MHz, continuous wave, klystrons driving a radio frequency quadrupole (RFQ). A phase control loop is necessary for each individual klystron in order to guarantee the phase matching of these klystrons. To meet this objective, they p… more
Date: December 31, 1998
Creator: Kwon, S.; Regan, A.; Wang, Y. M. & Rohlev, T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Nonlinear Pulsation Modeling of Luminous Blue Variables

Description: Using an updated version of the Ostlie and Cox (1993) nonlinear hydrodynamics code, we show the results of Luminous Blue Variable (LBV) envelope models based on evolution models of initial mass 50-80 M solar. including mass loss. The models use OPAL opacities, contain 60-120 Lagrangian zones, include time dependent convection, and are given an initial photospheric radial velocity amplitude of 1 km/sec. Our goal is to explain the reason for the LBV instability strip and suggest a cause for LBV o… more
Date: December 31, 1997
Creator: Despain, Kate M.; Guzik, Joyce A. & Cox, Arthur N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Nucleon-nucleon interactions

Description: Nucleon-nucleon interactions are at the heart of nuclear physics, bridging the gap between QCD and the effective interactions appropriate for the shell model. We discuss the current status of {ital NN} data sets, partial-wave analyses, and some of the issues that go into the construction of potential models. Our remarks are illustrated by reference to the Argonne {ital v}{sub 18} potential, one of a number of new potentials that fit elastic nucleon-nucleon data up to 350 MeV with a {Chi}{sup 2}… more
Date: December 31, 1996
Creator: Wiringa, R.B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Prospects of a baryon instability search in neutron-antineutron oscillations

Description: The purpose of this article is to review the current status and the future prospects for an experimental neutron-antineutron transition search. Traditional and new experimental techniques are discussed here. In the n {r_arrow} {anti n} search in experiments at existing reactors, it would be possible to increase the discovery potential up to four orders of magnitude for vacuum n {r_arrow} {anti n} transitions relative to the existing experimental level or to achieve the limit of {tau}{sub n-{ant… more
Date: December 31, 1996
Creator: Efremenko, Yu. & Kamyshkov, Yu.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Reaction theories for N* excitations in {pi}N and {gamma}N reactions

Description: The importance of developing reaction theories for investigating N* physics is illustrated in an analysis of pion photoproduction on the nucleon. It is shown that the {gamma}N {leftrightarrow} {Delta} transition amplitudes predicted by the constituent quark model are in agreement with the values extracted from the {gamma}N {r_arrow} {pi}N data only when the contributions from the reaction mechanisms calculated using a dynamical approach are taken into account in the analysis.
Date: December 31, 1996
Creator: Lee, T. S. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Vibration modal analysis using all-optical photorefractive processing

Description: A new experimental method for vibration modal analysis based on all- optical photorefractive processing is presented. The method utilizes an optical lock-in approach to measure phase variations in light scattered from optically rough, continuously vibrating surfaces. In this four-wave mixing technique, all-optical processing refers to mixing the object beam containing the frequency modulation due to vibration with a single frequency modulated pump beam in the photorefractive medium that process… more
Date: December 31, 1996
Creator: Hale, T. & Telschow, K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Amplitude and phase modulation with waveguide optics

Description: We have developed amplitude and phase modulation systems for glass lasers using integrated electro-optic modulators and solid state high- speed electronics. The present and future generation of lasers for Inertial Confinement Fusion require laser beams with complex temporal and phase shaping to compensate for laser gain saturation, mitigate parametric processes such as transverse stimulated Brillouin scattering in optics, and to provide specialized drive to the fusion targets. These functions c… more
Date: December 17, 1996
Creator: Burkhart, S. C.; Wilcox, R. B.; Browning, D. & Penko, F. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Experiment to measure total cross sections, differential cross sections and polarization effects in pp elastic scattering at RHIC

Description: The author is describing an experiment to study proton-proton (pp) elastic scattering experiment at the Relativistic Heavy Ion Collider (RHIC). Using both polarized and unpolarized beams, the experiment will study pp elastic scattering from {radical}s = 60 GeV to {radical}s = 500 GeV in two kinematical regions .In the Coulomb Nuclear Interference (CNI) region, 0.0005 < {vert_bar}t{vert_bar} < 0.12 (GeV/c){sup 2}, we will measure and study the s dependence of the total and elastic cross sections… more
Date: December 31, 1995
Creator: Guryn, W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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KN scattering in the nonrelativistic quark model

Description: KN scattering is of interest as a probe of nuclear structure and, more fundamentally, as a laboratory for the study of nonresonant hadron-hadron interactions. KN is a I theoretically attractive channel because of its simplicity, having only S = 1/2, no one pion exchange contributions and no valence q{anti q} annihilation. It may therefore be useful for the study of short-ranged quark forces analogous to the NN repulsive core. Since there are two isospin states, comparison of two closely related… more
Date: December 31, 1995
Creator: Barnes, F. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Theoretical aspects of light meson spectroscopy

Description: In this pedagogical review the authors discuss the theoretical understanding of light hadron spectroscopy in terms of QCD and the quark model. They begin with a summary of the known and surmised properties of QCD and confinement. Following this they review the nonrelativistic quark potential model for q{anti q} mesons and discuss the quarkonium spectrum and methods for identifying q{anti q} states. Finally, they review theoretical expectations for non-q{anti q} states (glueballs, hybrids and mu… more
Date: December 31, 1995
Creator: Barnes, T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The high energy behavior of the forward scattering parameters - an amplitude analysis update

Description: Utilizing the most recent experimental data, we reanalyze high energy pp and pp data, using the asymptotic amplitude analysis, under the assumption that we have reached {open_quotes}asymptopia{close_quotes}. This analysis gives strong evidence for a log (s/s{sub 0}) dependence at current energies and not log{sup 2} (s/s{sub 0}), and also demonstrates that odderons are not necessary to explain the experimental data.
Date: December 1995
Creator: Block, M. M.; Margolis, B. & White, A. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The E2/M1 mixing ratio in the excitation of the {Delta} from polarized photo-reactions

Description: In constituent quark models, a tensor interaction, mixing quark spins with their relative motion, is introduced to reproduce the observed baryon spectrum. This has a consequence completely analogous to the nuclear tensor force between the n and p in deuterium. A D state component is mixed into what would otherwise be a purely S-wave object. The D-wave component breaks spherical symmetry, resulting in a non-vanishing matrix element for the nucleon and a static quadrupole moment and deformation f… more
Date: December 1, 1993
Creator: Collaboration, The LEGS
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Hadron dynamics in high-energy pion-nucleus scattering

Description: It is argued that pion-nucleus scattering at high energy (above 300 MeV) is likely to be easier to interpret than it has been at lower energies where the {Delta}{sub 33} resonance dominates. We establish this by examining the relative importance of various dynamic ingredients of scattering theory for high-energy pions and comparing different versions of the theory: a ``model-exact`` microscopic optical model and an eikonal approximation. For nuclei as heavy as Ca, the eikonal theory is an excel… more
Date: December 31, 1992
Creator: Johnson, M. B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A tevatron collider beauty factory. [Final report, 1980--1992]

Description: This document which is labeled a final report consists of several different items. The first is a proposal for a detector to be developed for beauty physics. The detector is proposed for the Fermilab Tevatron, and would be designed to measure mixing reactions, rare decay modes, and even CP violation in hadron collider beauty production. The general outline of the work proposed is given, and an estimate of the time to actually design the detector is presented, along with proposed changes to the … more
Date: December 31, 1992
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Inelastic Electron Scattering From Surfaces. Progress Report for Second Grant Year

Description: This report contains highlights of accomplishments of the past year, for the University of California, Irvine and the University of Wisconsin, Milwaukee collaboration on surface excitations, and their interactions with low energy electrons. In addition, we present a summary of future research to be carried out in the coming grant year.
Date: December 31, 1991
Creator: Tong, S. Y. & Mills, D. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Narrow structure in {Lambda}d scattering near the {Sigma} threshold ({sub {Sigma}}{sup 3}He states)

Description: A separable-potential, Faddeev-type calculation of {Lambda}-deuteron scattering near the threshold for {Sigma} production is shown to produce structure (a resonance peak) in the cross section which lies below the {Sigma} threshold for two different YN ({Lambda}N-{Sigma}N coupled-channel) potential models. In one case the {Sigma}NN eigenvalue corresponds to a pole which lies below threshold (bound) and in the second case the poles lies above the threshold.
Date: December 31, 1991
Creator: Gibson, B. F. & Afnan, I. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Resonant and non-resonant magnetic scattering

Description: The tunability and the polarization of synchrotron radiation open upon new possibilities for the study of magnetism. Studies on magnetic materials performed at the National Synchrotron Light Source are reviewed, and thy fall into four areas: structure, evolution of magnetic order, separation of L and S, and resonance effects. In the vicinity of atomic absorption edges, the Faraday effect, magnetic circular dichroism, and resonant magnetic scattering are all related resonance effects which measu… more
Date: December 31, 1991
Creator: McWhan, D. B.; Hastings, J. B.; Kao, C. C. & Siddons, D. P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Ringwaldmania reconsidered

Description: The exciting possibility that anomalous baryon and lepton number violation might be observable at the next generation of supercolliders is suggested by an instanton calculation due to Ringwald and Espinoa. Here, the current controversial status of these claims is discussed, and progress on several fronts is described.
Date: December 31, 1991
Creator: Mattis, M. P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Techniques in meson spectroscopy

Description: This report contains lectures on the following topics: the quark model and beyond using quantum chromodynamics; analysis of formation reactions; energy dependence of the partial wave amplitudes; where the data for the t-matrix analysis comes from; and coupled channel analysis of isoscalar mesons.
Date: December 31, 1991
Creator: Longacre, R. S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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