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Delta f Monte Carlo Calculation Of Neoclassical Transport In Perturbed Tokamaks

Description: Non-axisymmetric magnetic perturbations can fundamentally change neoclassical transport in tokamaks by distorting particle orbits on deformed or broken flux surfaces. This so-called non-ambipolar transport is highly complex, and eventually a numerical simulation is required to achieve its precise description and understanding. A new delta#14;f particle code (POCA) has been developed for this purpose using a modi ed pitch angle collision operator preserving momentum conservation. POCA was succes… more
Date: April 11, 2012
Creator: Kimin Kim, Jong-Kyu Park, Gerrit Kramer and Allen H. Boozer
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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PTRANSP Tests Of TGLF And Predictions For ITER

Description: One of the physics goals for ITER is to achieve high fusion power PDT at a high gain QDT. This goal is important for studying the physics of reactor-relevant burning plasmas. Simulations of plasma performance in ITER can help achieve this goal by aiding in the design of systems such as diagnostics and in planning ITER plasma regimes. Simulations can indicate areas where further research in theory and experiments is needed. To have credible simulations integrated modeling is necessary since plas… more
Date: February 28, 2012
Creator: Budny, Robert V.; Yuan, Xingqiu; Jardin, S.; Hammett, G. & Staebler, G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Simulation of the IBM System/7

Description: This thesis describes the simulation of the IBM SYSTEM/7. The research leading to this thesis involved the development of a PL/I computer program that runs on an IBM 360/50 computer and simulates the IBM SYSTEM/7. Various methods of simulation are examined and guidelines for computer simulation of another computer are established. The SYSTEM/7 simulator (SIM/7) is the heart of this thesis. SIM/7 simulates the IBM SYSTEM/7 entirely with software as opposed to an emulator which involves the combi… more
Date: May 1977
Creator: Lewis, Ted C.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Comparison of Gas Puff Imaging Data in NSTX with the DEGAS 2 Simulation

Description: Gas-Pu -Imaging (GPI) is a two dimensional diagnostic which measures the edge Dα light emission from a neutral Dα gas puff near the outer mid- plane of the National Spherical Torus Experiment (NSTX). DEGAS 2 is a 3-D Monte Carlo code used to model neutral transport and plasma-neutral interactions in fusion plasmas. In this paper, we compare the measured and modeled Dα light emission for speci c NSTX experiments. Both the simulated spatial distribution and radiance of the Dα light emission agree… more
Date: April 10, 2013
Creator: Cao, B.; Stotler, D. P.; Zweben, S. J.; Bell, M.; Diallo, A. & LeBlanc, B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Three-dimensional Numerical Investigation of Electron Transport with Rotating Spoke in a Cylindrical Anode Layer Hall Plasma Accelerator

Description: The oscillation behavior described in [Tang et. al, Phys. Plasmas 19, 073519 (2012)] di ers too greatly from previous experimental and numerical studies to claim observation of the same phenomenon. Most signi cantly, the rotation velocity in [Tang et. al, Phys. Plasmas 19, 073519 (2012)] is three orders of magnitude larger than that of typical \rotating spoke" phenomena. Several physical and numerical considerations are presented to more accurately understand the numerical results of [Tang… more
Date: August 27, 1012
Creator: Ellison, C. Leland; Matyash, K.; Parker, J. B.; Raitses, Y. & Fisch, N. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Three-dimensional Simulation of Gas Conductance Measurement Experiments on Alcator C-Mod

Description: Three-dimensional Monte Carlo neutral transport simulations of gas flow through the Alcator C-Mod subdivertor yield conductances comparable to those found in dedicated experiments. All are significantly smaller than the conductance found with the previously used axisymmetric geometry. A benchmarking exercise of the code against known conductance values for gas flow through a simple pipe provides a physical basis for interpreting the comparison of the three-dimensional and experimental C-Mod con… more
Date: June 15, 2004
Creator: Stotler, D. P. & LaBombard, B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Library CD-ROM LAN Performance and Patron Use: a Computer Simulation Model

Description: In this study, a computer simulation model for library CD-ROM LAN systems was created. Using this model, the system optimization problems were examined. The simulation model imitated the process of the actual decision variables changing their values and generated the corresponding results. Under a certain system environment, if the values of decision variables are changing, the system performances are getting changed also. This study investigated these relationships with the created model. The … more
Date: May 1996
Creator: Xia, Hong
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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The Validation of Interactive Computer Simulation Programs for Predicting On-Task Competencies for Inertial Navigation System Equipment

Description: This study investigated the predictive value of time on-task and error scores on tests administered through Control Data Corporation PLATO interactive computer graphics simulation as predictors of errors and time on-task for inertial navigation system equipment operation. In addition, the correlation between simulated pass/fail error and time on-task scores, and subsequent pass/fail criteria using actual equipment was investigated.
Date: May 1983
Creator: Hageman, Dwight C. (Dwight Conrad)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Pedestal Fueling Simulations with a Coupled Kinetic-kinetic Plasma-neutral Transport Code

Description: A Monte Carlo neutral transport routine, based on DEGAS2, has been coupled to the guiding center ion-electron-neutral neoclassical PIC code XGC0 to provide a realistic treatment of neutral atoms and molecules in the tokamak edge plasma. The DEGAS2 routine allows detailed atomic physics and plasma-material interaction processes to be incorporated into these simulations. The spatial pro le of the neutral particle source used in the DEGAS2 routine is determined from the uxes of XGC0 ions to the ma… more
Date: August 29, 2012
Creator: D.P. Stotler, C.S. Chang, S.H. Ku, J. Lang and G.Y. Park
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Nonequilibrium Gyrokinetic Fluctuation Theory and Sampling Noise in Gyrokinetic Particle-in-cell Simulations

Description: The present state of the theory of fluctuations in gyrokinetic GK plasmas and especially its application to sampling noise in GK particle-in-cell PIC simulations is reviewed. Topics addressed include the Δf method, the fluctuation-dissipation theorem for both classical and GK many-body plasmas, the Klimontovich formalism, sampling noise in PIC simulations, statistical closure for partial differential equations, the theoretical foundations of spectral balance in the presence of arbitrary noise s… more
Date: October 9, 2007
Creator: Krommes, John A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Computer Simulation of Particulate Systems

Description: From Introduction: "The first objective of he present Bureau research was the development of a means to model random assemblies of circles and spheres that would accurately simulate actual particulate systems. The second objective of this research was to develop the computer simulations to the point where they could be used to predict real packaging or covering properties and to develop a body of data that could be used to improve and add to what is currently known about the statistical geometr… more
Date: 1971
Creator: Norman, Lindsay D.; Maust, Edwin E., Jr. & Skolnick, Leonard P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Gauge Properties Of The Guiding Center Variational Symplectic Integrator

Description: Recently, variational symplectic algorithms have been developed for the long-time simulation of charged particles in magnetic fields1-3. As a direct consequence of their derivation from a discrete variational principle, these algorithms have very good long-time energy conservation, as well as exactly preserving discrete momenta. We present stability results for these algorithms, focusing on understanding how explicit variational integrators can be designed for this type of system. It is found t… more
Date: March 5, 2012
Creator: J. Squire, H. Qin and W. Tang
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Steady State Turbulent Transport in Magnetic Fusion Plasmas

Description: For more than a decade, the study of microturbulence, driven by ion temperature gradient (ITG) drift instabilities in tokamak devices, has been an active area of research in magnetic fusion science for both experimentalists and theorists alike. One of the important impetus for this avenue of research was the discovery of the radial streamers associated the ITG modes in the early nineties using a Particle-In-Cell (PIC) code. Since then, ITG simulations based on the codes with increasing realism … more
Date: December 20, 2007
Creator: W.W. Lee, S. Ethier, R. Kolesnikov, W.X. Wang, and W.M. Tang
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Benchmarking Nonlinear Turbulence Simulations on Alcator C-Mod

Description: Linear simulations of plasma microturbulence are used with recent radial profiles of toroidal velocity from similar plasmas to consider nonlinear microturbulence simulations and observed transport analysis on Alcator C-Mod. We focus on internal transport barrier (ITB) formation in fully equilibrated H-mode plasmas with nearly flat velocity profiles. Velocity profile data, transport analysis and linear growth rates are combined to integrate data and simulation, and explore the effects of toroida… more
Date: June 22, 2004
Creator: Redi, M.H.; Fiore, C.L.; Dorland, W.; Greenwald, M.J.; Hammett, G.W.; Hill, K. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Computer Simulations of Dilute Polymer Solutions: Chain Overlaps and Entanglements

Description: Chain conformations and the presence of chain overlaps and entanglements in dilute polymer solutions have been analyzed. The fundamental problem of existence of chain overlaps in dilute solutions is related to the drag reduction phenomenon (DR). Even though DR occurs in solutions with the concentration of only few parts per million (ppm), some theories suggest that entanglements may play an important role in DR mechanism. Brownian dynamics technique have been used to perform simulations of dilu… more
Date: August 1996
Creator: Drewniak, Marta
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

The Effect on Stellarator Neoclassical Transport of a Fluctuating Electrostatic Spectrum

Description: We study the effect on neoclassical transport of applying a fluctuating electrostatic spectrum, such as produced either by plasma turbulence, or imposed externally. For tokamaks, it is usually assumed that the neoclassical and ''anomalous'' contributions to the transport roughly superpose, D = D{sub nc} + D{sub an}, an intuition also used in modeling stellarators. An alternate intuition, however, is one where it is the collisional and anomalous scattering frequencies which superpose, {nu}{sub e… more
Date: November 23, 2004
Creator: Mynick, H. E. & Boozer, A. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Analog Simulation of the Hanford N-Reactor Plant, Part 1: Description of the Overall Simulation Model

Description: Report that describes Hanford Laboratories' overall N-Reactor plant simulation model and its use to study the characteristics of the plant, plant operational procedures, and the effects of plant, operator, and control system malfunctions.
Date: September 1, 1964
Creator: Swanson, C. D.; Coughren, K. D.; Dionne, P. J. & Thieme, G. G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Computer Science Research Institute 2004 annual report of activities.

Description: This report summarizes the activities of the Computer Science Research Institute (CSRI) at Sandia National Laboratories during the period January 1, 2004 to December 31, 2004. During this period the CSRI hosted 166 visitors representing 81 universities, companies and laboratories. Of these 65 were summer students or faculty. The CSRI partially sponsored 2 workshops and also organized and was the primary host for 4 workshops. These 4 CSRI sponsored workshops had 140 participants--74 from univers… more
Date: March 1, 2006
Creator: DeLap, Barbara J.; Womble, David Eugene & Ceballos, Deanna Rose
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Developing algorithms for predicting protein-protein interactions of homology modeled proteins.

Description: The goal of this project was to examine the protein-protein docking problem, especially as it relates to homology-based structures, identify the key bottlenecks in current software tools, and evaluate and prototype new algorithms that may be developed to improve these bottlenecks. This report describes the current challenges in the protein-protein docking problem: correctly predicting the binding site for the protein-protein interaction and correctly placing the sidechains. Two different and co… more
Date: January 1, 2006
Creator: Martin, Shawn Bryan; Sale, Kenneth L.; Faulon, Jean-Loup Michel & Roe, Diana C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Simulation of Optical and Synthetic Imaging using Microwave Reflectometry

Description: Two-dimensional full-wave time-dependent simulations in full plasma geometry are presented which show that conventional reflectometry (without a lens) can be used to synthetically image density fluctuations in fusion plasmas under conditions where the parallel correlation length greatly exceeds the poloidal correlation length of the turbulence. The advantage of synthetic imaging is that the image can be produced without the need for a large lens of high optical quality, and each frequency that … more
Date: January 16, 2004
Creator: Kramer, G. J.; Nazikian, R. & Valeo, E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Computer Science Research Institute 2003 annual report of activities.

Description: This report summarizes the activities of the Computer Science Research Institute (CSRI) at Sandia National Laboratories during the period January 1, 2003 to December 31, 2003. During this period the CSRI hosted 164 visitors representing 78 universities, companies and laboratories. Of these 78 were summer students or faculty members. The CSRI partially sponsored 5 workshops and also organized and was the primary host for 3 workshops. These 3 CSRI sponsored workshops had 178 participants--137 fro… more
Date: March 1, 2006
Creator: DeLap, Barbara J.; Womble, David Eugene & Ceballos, Deanna Rose
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Application of Field Measurements and Computer Modeling to Evaluate Deep Mine Shaft Stability in Northern Idaho

Description: Abstract: Researchers at the U.S. Bureau of Mines have developed personal-computer-based data acquisition, instrumentation, and mine visualization and modeling techniques to evaluate a mine accessway in a deep hard-rock mine in northern Idaho. These techniques were applied to a mine shaft in a large silver mine that has been in operation for many years. A very deep, rectangular, timber-supported shaft extending to depths exceeding 2.3 km (7,500 ft) had been deforming continuously as a result of… more
Date: 1996
Creator: Beus, Michael J.; Orr, T. J. & Whyatt, J. K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Forest Landscape Dynamics: a Semi-Markov Modeling Approach

Description: A transition model (MOSAIC) is used to describe forest dynamics at the landscape scale. The model uses a semi-Markov framework by considering transition probabilities and Erlang distributed holding times in each transition. Parameters for the transition model are derived from a gap model (ZELIG). This procedure ensures conceptual consistency of the landscape model with the fine scale ecological detail represented by the forest gap model. Spatial heterogeneity in the transition model is driven b… more
Date: August 1997
Creator: Ablan, Magdiel
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Structural Analysis of the NCSX Vacuum Vessel

Description: The NCSX (National Compact Stellarator Experiment) vacuum vessel has a rather unique shape being very closely coupled topologically to the three-fold stellarator symmetry of the plasma it contains. This shape does not permit the use of the common forms of pressure vessel analysis and necessitates the reliance on finite element analysis. The current paper describes the NCSX vacuum vessel stress analysis including external pressure, thermal, and electro-magnetic loading from internal plasma disru… more
Date: September 28, 2004
Creator: Dahlgren, Fred; Brooks, Art; Goranson, Paul; Cole, Mike & Titus, Peter
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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