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Atomic Emission, Absorption and Fluorescence in the Laser-induced Plasma

Description: The main result of our efforts is the development and successful application of the theoretical model of laser induced plasma (LIP) that allows a back-calculation of the composition of the plasma (and the condensed phase) based on the observable plasma spectrum. The model has an immediate experimental input in the form of LIP spectra and a few other experimentally determined parameters. The model is also sufficiently simple and, therefore, practical. It is conveniently interfaced in a graphical… more
Date: January 22, 2009
Creator: Winefordner, J. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Final Report for grant DE-FG02-06ER54888, "Simulation of Beam-Electron Cloud Interactions in Circular Accelerators Using Plasma Models"

Description: The primary goal of this collaborative proposal was to modify the code QuickPIC and apply it to study the long-time stability of beam propagation in low density electron clouds present in circular accelerators. The UCLA contribution to this collaborative proposal was in supporting the development of the pipelining scheme for the QuickPIC code, which extended the parallel scaling of this code by two orders of magnitude.
Date: November 27, 2012
Creator: Decyk, Viktor K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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THE TORMAC V EXPERIMENT

Description: Tormac (Toroidal Magnetic Cusp) is a plasma confinement concept combining the favorable MHD stability properties of a cusp geometry with the good particle confinement inherent to closed field geometry, A Tormac plasma has two regions: an interior region in which a toroidal bias or studding field is embedded, and an exterior or surface region confined by mirror trapping along open field lines. The combination of these two regions is expected to lead to a configuration having confinement substant… more
Date: March 1, 1980
Creator: Brown, I. G.; Feinberg, B.; Kunkel, W. B.; Levine, M. A.; Niland, R. A.; Shaw, R. S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Center for the Study of Plasma Microturbulence

Description: We have discovered a possible "natural fueling" mechanism in tokamak fusion reactors using large scale gyrokinetic turbulence simulation. In the presence of a heat flux dominated tokamak plasma, cold ions naturally pinch radially inward. If cold DT fuel is introduced near the edge using shallow pellet injection, the cold fuel will pinch inward, at the expense of hot helium ash going radially outward. By adjusting the cold DT fuel concentration, the core DT density profiles can be maintained. We… more
Date: March 2, 2012
Creator: Parker, Scott E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Guiding Center Equations for Ideal Magnetohydrodynamic Modes

Description: Guiding center simulations are routinely used for the discovery of mode-particle resonances in tokamaks, for both resistive and ideal instabilities and to find modifications of particle distributions caused by a given spectrum of modes, including large scale avalanches during events with a number of large amplitude modes. One of the most fundamental properties of ideal magnetohydrodynamics is the condition that plasma motion cannot change magnetic topology. The conventional representation of id… more
Date: February 21, 2013
Creator: White, Roscoe B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Scaling to 150K cores: recent algorithm and performance engineering developments enabling XGC1 to run at scale

Description: Particle-in-cell (PIC) methods have proven to be eft#11;ective in discretizing the Vlasov-Maxwell system of equations describing the core of toroidal burning plasmas for many decades. Recent physical understanding of the importance of edge physics for stability and transport in tokamaks has lead to development of the fi#12;rst fully toroidal edge PIC code - XGC1. The edge region poses special problems in meshing for PIC methods due to the lack of closed flux surfaces, which makes fi#12;eld-line… more
Date: October 1, 2009
Creator: Adams, Mark F.; Ku, Seung-Hoe; Worley, Patrick; D'Azevedo, Ed; Cummings, Julian C. & Chang, C. S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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STATISTICAL ANALYSIS OF A DETERMINISTIC STOCHASTIC ORBIT

Description: If the solution of a deterministic equation is stochastic (in the sense of orbital instability), it can be subjected to a statistical analysis. This is illustrated for a coded orbit of the Chirikov mapping. Statistical dependence and the Markov assumption are tested. The Kolmogorov-Sinai entropy is related to the probability distribution for the orbit.
Date: May 1, 1980
Creator: Kaufman, Allan N.; Abarbanel, Henry D.I. & Grebogi, Celso
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Trade Study Analysis for TNS Tokamaks.

Description: A series of parametric trade studies was performed to consistently evaluate the relative.costs and performance parameters of D-T burning tokamaks over a range of plasma sizes and toroidal field (TF) coil technologies. Four different types of TF coil technologies were investigated: water-cooled copper coils, superconducting NbTi and Nb{sub 3}Sn coils, and a "hybrid" coil arrangement consisting of a· normal conducting Cu coil nested within a superconducting NbTi coil. Results of the ana… more
Date: September 30, 1977
Creator: Chapin, D. L.; Garber, H. J.; Sink, D. A. & Gibson, G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Theoretical and Experimental Studies of Magneto-Rayleigh-Taylor Instabilities

Description: Magneto-Rayleigh-Taylor instability (MRT) is important to magnetized target fusion, wire-array z-pinches, and equation-of-state studies using flyer plates or isentropic compression. It is also important to the study of the crab nebula. The investigators performed MRT experiments on thin foils, driven by the mega-ampere linear transformer driver (LTD) facility completed in their laboratory. This is the first 1-MA LTD in the USA. Initial experiments on the seeding of MRT were performed. Also comp… more
Date: July 7, 2013
Creator: Lau, Yue Ying & Gilgenbach, Ronald
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Flow Shear Effects in the Onset Physics of Resistive MHD Instabilities in Tokamaks. Final report

Description: The progress in this research centers around the computational analysis of flow shear effects in the onset of a 3/2 mode driven by a 1/1 mode in DIII-D equilibria. The initial idea was to try and calculate, via nonlinear simulations with NIMROD, the effects of rotation shear on driven 3/2 and 2/1 seed island physics, in experimentally relevant DIIID equilibria. The simulations indicated that very small seed islands were directly driven, as shielding between the sawtooth and the surfaces is sign… more
Date: April 24, 2013
Creator: Brennan, Dylan P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Power Supply Changes for NSTX Resistive Wall Mode Coils

Description: The National Spherical Torus Experiment (NSTX) has been designed and installed in the existing facilities at Princeton Plasma Physics Laboratory (PPPL). Most of the hardware, plant facilities, auxiliary sub-systems, and power systems originally used for the Tokamak Fusion Test Reactor (TFTR) have been used with suitable modifications to reflect NSTX needs. Prior to 2004, the NSTX power system was feeding twelve (12) circuits in the machine. In 2004 the Resistive Wall Mode (RWM) Coils were insta… more
Date: June 28, 2013
Creator: Ramakrishnan, S S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Full Toroidal Imaging of Non-axisymmetric Plasma Material Interaction in the National Spherical Torus eXperiment

Description: A pair of two dimensional fast cameras with a wide angle view (allowing a full radial and toroidal coverage of the lower divertor) was installed in the National Spherical Torus Experiment in order to monitor non-axisymmetric effects. A custom polar remapping procedure and an absolute photometric calibration enabled the easier visualization and quantitative analysis of non-axisymmetric plasma material interaction (e.g., strike point splitting due to application of 3D fields and effects of toroid… more
Date: July 11, 2012
Creator: Filippo Scotti, A.L. Roquemore, and V. A. Soukhanovskii
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Growth and phase velocity of self-modulated beam-driven plasma waves

Description: A long, relativistic particle beam propagating in an overdense plasma is subject to the self-modulation instability. This instability is analyzed and the growth rate is calculated, including the phase relation. The phase velocity of the wake is shown to be significantly less than the beam velocity. These results indicate that the energy gain of a plasma accelerator driven by a self-modulated beam will be severely limited by dephasing. In the long-beam, strongly-coupled regime, dephasing is reac… more
Date: September 20, 2011
Creator: Benedetti, Carlo; Esarey, Eric; Gruener, Florian & Leemans, Wim
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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First Generation Final Focusing Solenoid For NDCX-I

Description: This report describes the prototype final focus solenoid (FFS-1G), or 1st generation FFS. In order to limit eddy currents, the solenoid winding consists of Litz wire wound on a non-conductive G-10 tube. For the same reason, the winding pack was inserted into an electrically insulating, but thermally conducting Polypropylene (Cool- Poly© D1202) housing and potted with highly viscous epoxy (to be able to wick the single strands of the Litz wire). The magnet is forced-air cooled through cooling ch… more
Date: November 9, 2011
Creator: Seidl, P. A. & Waldron, W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Hardwired Control Changes For NSTX DC Power Feeds

Description: The National Spherical Torus Experiment (NSTX) has been designed and installed in the existing facilities at Princeton Plasma Physics Laboratory (PPPL). Most of the hardware, plant facilities, auxiliary sub-systems, and power systems originally used for the Tokamak Fusion Test Reactor (TFTR) have been used with suitable modifications to reflect NSTX needs. The original TFTR Hardwired Control System (HCS) with electromechanical relays was used for NSTX DC Power loop control and protection during… more
Date: June 28, 2013
Creator: Ramakrishnan, S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Why is Boris Algorithm So Good?

Description: Due to its excellent long term accuracy, the Boris algorithm is the de facto standard for advancing a charged particle. Despite its popularity, up to now there has been no convincing explanation why the Boris algorithm has this advantageous feature. In this letter, we provide an answer to this question. We show that the Boris algorithm conserves phase space volume, even though it is not symplectic. The global bound on energy error typically associated with symplectic algorithms still holds for … more
Date: March 3, 2013
Creator: Qin, Hong; Zhang, Shuangxi; Xiao, Jianyuan & Tang, William M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Local Effects of Biased Electrodes in the Divertor of NSTX

Description: The goal of this paper is to characterize the effects of small non-axisymmetric divertor plate electrodes on the local scrape-off layer plasma. Four small rectangular electrodes were installed into the outer divertor plates of NSTX. When the electrodes were located near the outer divertor strike point and biased positively, there was an increase in the nearby probe currents and probe potentials and an increase in the LiI light emission at the large major radius end of these electrodes. When an … more
Date: May 7, 2012
Creator: : S. Zweben, M.D. Campanell, B.C. Lyons, R.J. Maqueda, Y. Raitses, A.L. Roquemore and F. Scotti
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Use of Polycarbonate Vacuum Vessels in High-Temperature Fusion-Plasma Research

Description: Magnetic fusion energy (MFE) research requires ultrahigh-vacuum (UHV) conditions, primarily to reduce plasma contamination by impurities. For radiofrequency (RF)-heated plasmas, a great benefit may accrue from a non-conducting vacuum vessel, allowing external RF antennas which avoids the complications and cost of internal antennas and high-voltage high-current feedthroughs. In this paper we describe these and other criteria, e.g., safety, availability, design flexibility, structural integrity, … more
Date: September 27, 2012
Creator: B. Berlinger, A. Brooks, H. Feder, J. Gumbas, T. Franckowiak and S.A. Cohen
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Perspective on the Role of Negative Ions and Ion-Ion Plasmas in Heavy Ion Fusion Science, Magnetic Fusion Energy, and Related Fields

Description: Some years ago it was suggested that halogen negative ions [1] could offer a feasible alternative path to positive ions as a heavy ion fusion driver beam which would not suffer degradation due to electron accumulation in the accelerator and beam transport system, and which could be converted to a neutral beam by photodetachment near the chamber entrance if desired. Since then, experiments have demonstrated that negative halogen beams can be extracted and accelerated away from the gas plume near… more
Date: August 12, 2008
Creator: Kwan, L. Grisham and J.W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Final Technical Report

Description: Final Technical Report for U.S. Department of Energy Grant No. DE-FG02-09ER55005 Nonlinear FLR Effects in Reduced Fluid Models Alain J. Brizard, Saint Michael™s College The above-mentioned DoE grant was used to support research activities by the PI during a sabbatical leave from Saint Michael™s College in 2009. The major focus of the work was the role played by guiding-center and gyrocenter (linear and nonlinear) polarization and magnetization effects in understanding transport processes … more
Date: 2009
Creator: Brizard, Alain J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Physics Design of a 28 GHz Electron Heating System for the National Spherical Torus Experiment Upgrade

Description: A megawatt-level, 28 GHz electron heating system is being designed to support non-inductive (NI) plasma current (I{sub p}) start-up and local heating and current drive (CD) in H-mode discharges in the National Spherical Torus Experiment Upgrade (NSTX-U). The development of fully NI I{sub p} start-up and ramp-up is an important goal of the NSTX-U research program. 28 GHz electron cyclotron (EC) heating is predicted to rapidly increase the central electron temperature (T{sub e}(0)) of low density… more
Date: July 9, 2013
Creator: Taylor, G.; Bertelli, N.; Ellis, R. A.; Gerhardt, S. P.; Harvey, R. W.; Hosea, J. C. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Current-Driven Filament Instabilities in Relativistic Plasmas. Final report

Description: This grant has supported a study of some fundamental problems in current- and flow-driven instabilities in plasmas and their applications in inertial confinement fusion (ICF) and astrophysics. It addressed current-driven instabilities and their roles in fast ignition, and flow-driven instabilities and their applications in astrophysics.
Date: February 13, 2013
Creator: Ren, Chuang
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Advanced Design Studies. Final report

Description: The ARIES-CS project was a multi-year multi-institutional project to assess the feasibility of a compact stellarator as a fusion power plant. The work herein describes efforts to help design one aspect of the device, the divertor, which is responsible for the removal of particle and heat flux from the system, acting as the first point of contact between the magnetically confined hot plasma and the outside world. Specifically, its location and topology are explored, extending previous work on th… more
Date: December 1, 2012
Creator: Steiner, Don
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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