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2-D electric fields and drifts near the magnetic separatrix in divertor tokamaks

2-D electric fields and drifts near the magnetic separatrix in divertor tokamaks

Date: November 15, 1998
Creator: Mattor, N.; Porter, G. D.; Rognlien, T. D. & Ryutov, D. D.
Description: A 2-D calculation is presented for the transport of plasma in the edge region of a divertor tokamak solving continuity, momentum, and energy balance fluid equations. The model uses anomalous radial diffusion, including perpendicular ion momentum, and classical cross-field drifts transport. Parallel and perpendicular currents yield a self-consistent electrostatic potential on both sides of the magnetic separatrix. Outside the separatrix, the simulation extends to material divertor plates where the incident plasma is recycled as neutral gas and where the plate sheath and parallel currents dominate the potential structure. Inside the separatrix, various radial current terms - from viscosity, charge-exchange and poloidal damping, inertia, and {triangledown}B - contribute to the determining the potential. The model rigorously enforces cancellation of gyro-viscous and magnetization terms from the transport equations. The results emphasize the importance of E x B particle flow under the X-point which depends on the sign of the toroidal magnetic field. Radial electric field (E{sub y}) profiles at the outer midplane are small with weak shear when high L-mode diffusion coefficients are used and are large with strong shear when smaller H-mode diffusion coefficients are used. The magnitude and shear of the electric field (E{sub y}) is larger both when the ...
Contributing Partner: UNT Libraries Government Documents Department
2-D Finite Element Cable and Box IEMP Analysis

2-D Finite Element Cable and Box IEMP Analysis

Date: December 17, 1998
Creator: Scivner, G.J. & Turner, C.D.
Description: A 2-D finite element code has been developed for the solution of arbitrary geometry cable SGEMP and box IEMP problems. The quasi- static electric field equations with radiation- induced charge deposition and radiation-induced conductivity y are numerically solved on a triangular mesh. Multiple regions of different dielectric materials and multiple conductors are permitted.
Contributing Partner: UNT Libraries Government Documents Department
2-D image segmentation using minimum spanning trees

2-D image segmentation using minimum spanning trees

Date: September 1995
Creator: Xu, Y. & Uberbacher, E. C.
Description: This paper presents a new algorithm for partitioning a gray-level image into connected homogeneous regions. The novelty of this algorithm lies in the fact that by constructing a minimum spanning tree representation of a gray-level image, it reduces a region partitioning problem to a minimum spanning tree partitioning problem, and hence reduces the computational complexity of the region partitioning problem. The tree-partitioning algorithm, in essence, partitions a minimum spanning tree into subtrees, representing different homogeneous regions, by minimizing the sum of variations of gray levels over all subtrees under the constraints that each subtree should have at least a specified number of nodes, and two adjacent subtrees should have significantly different average gray-levels. Two (faster) heuristic implementations are also given for large-scale region partitioning problems. Test results have shown that the segmentation results are satisfactory and insensitive to noise.
Contributing Partner: UNT Libraries Government Documents Department
2-D Imaging of Electron Temperature in Tokamak Plasmas

2-D Imaging of Electron Temperature in Tokamak Plasmas

Date: July 8, 2004
Creator: Munsat, T.; Mazzucato, E.; Park, H.; Domier, C.W.; Johnson, M.; Jr., N.C. Luhmann et al.
Description: By taking advantage of recent developments in millimeter wave imaging technology, an Electron Cyclotron Emission Imaging (ECEI) instrument, capable of simultaneously measuring 128 channels of localized electron temperature over a 2-D map in the poloidal plane, has been developed for the TEXTOR tokamak. Data from the new instrument, detailing the MHD activity associated with a sawtooth crash, is presented.
Contributing Partner: UNT Libraries Government Documents Department
2-D linear motion system. Innovative technology summary report

2-D linear motion system. Innovative technology summary report

Date: November 1, 1998
Creator: unknown
Description: The US Department of Energy's (DOE's) nuclear facility decontamination and decommissioning (D and D) program requires buildings to be decontaminated, decommissioned, and surveyed for radiological contamination in an expeditious and cost-effective manner. Simultaneously, the health and safety of personnel involved in the D and D activities is of primary concern. D and D workers must perform duties high off the ground, requiring the use of manlifts or scaffolding, often, in radiologically or chemically contaminated areas or in areas with limited access. Survey and decontamination instruments that are used are sometimes heavy or awkward to use, particularly when the worker is operating from a manlift or scaffolding. Finding alternative methods of performing such work on manlifts or scaffolding is important. The 2-D Linear Motion System (2-D LMS), also known as the Wall Walker{trademark}, is designed to remotely position tools and instruments on walls for use in such activities as radiation surveys, decontamination, and painting. Traditional (baseline) methods for operating equipment for these tasks require workers to perform duties on elevated platforms, sometimes several meters above the ground surface and near potential sources of contamination. The Wall Walker 2-D LMS significantly improves health and safety conditions by facilitating remote operation of equipment. ...
Contributing Partner: UNT Libraries Government Documents Department
A 2-D Pore-Network Model of the Drying of Single-Component Liquids in Porous Media

A 2-D Pore-Network Model of the Drying of Single-Component Liquids in Porous Media

Date: January 20, 2000
Creator: Yortsos, Yanic C.; Yiotis, A. G.; Stubos, A. K. & Boundovis, A. G.
Description: The drying of liquid-saturated porous media is typically approaching using macroscopic continuum models involving phenomenological coefficients. Insight on these coefficients can be obtained by a more fundamental study at the pore- and pore-network levels. In this report, a model based on pore-network representation of porous media that accounts for various process at the pore-scale is presented. These include mass transfer by advection and diffusion in the gas phase, viscous flow in liquid and gas phases and capillary effects at the gas-liquid menisci in the pore throats.
Contributing Partner: UNT Libraries Government Documents Department
A 2-D Self-Consistent DSMC Model for Chemically Reacting Low Pressure Plasma Reactors

A 2-D Self-Consistent DSMC Model for Chemically Reacting Low Pressure Plasma Reactors

Date: June 17, 1999
Creator: Bartel, Timothy J.; Economou, Demetre & Johannes, Justine E.
Description: This paper will focus on the methodology of using a 2D plasma Direct Simulation Monte Carlo technique to simulate the species transport in an inductively coupled, low pressure, chemically reacting plasma system. The pressure in these systems is typically less than 20 mtorr with plasma densities of approximately 10{sup 17} {number_sign}/m{sup 3} and an ionization level of only 0.1%. This low ionization level tightly couples the neutral, ion, and electron chemistries and interactions in a system where the flow is subsonic. We present our strategy and compare simulation results to experimental data for Cl{sub 2} in a Gaseous Electronics Conference (GEC) reference cell modified with an inductive coil.
Contributing Partner: UNT Libraries Government Documents Department
2-D Simulations of Drainage Winds and Diffusion Compared to Observations

2-D Simulations of Drainage Winds and Diffusion Compared to Observations

Date: May 29, 2001
Creator: Garrett, A.J.
Description: A vertically integrated dynamical drainage flow model is developed from conservation equations for momentum and mass in a terrain-following coordinate system. Wind fields from the dynamical model drive a Monte Carlo transport and diffusion model. The model needs only topographic data, an Eulerian or Lagrangian time scale and a surface drag coefficient for input data, and can be started with a motionless atmosphere. Model wind and diffusion predictions are compared to observations from the rugged Geysers CA area. Model winds generally agree with observed surface winds, and in some cases may give better estimates of area-averaged flow than point observations. Tracer gas concentration contours agree qualitatively with observed contours, and point predictions of maximum concentrations were correctly predicted to within factors of 2 to 10. Standard statistical tests of model skill showed that the accuracy of the predictions varied significantly from canyon to canyon in the Geysers are a. Model wind predictions are also compared to observations from the Savannah River Plant of SC which has gently rolling terrain. The model correctly simulated the slower development of drainage winds and slower deepening of the drainage layer in the Savannah River Valley, relative to the Geysers CA simulations. The SC simulations ...
Contributing Partner: UNT Libraries Government Documents Department
2 HZ, 30 T SPLIT PULSE WATER COOLED MAGNET FOR NEUTRON SCATTERING EXPERIMENTS (MATERIALS CHARACTERIZATION AND DESIGN OPTIONS)

2 HZ, 30 T SPLIT PULSE WATER COOLED MAGNET FOR NEUTRON SCATTERING EXPERIMENTS (MATERIALS CHARACTERIZATION AND DESIGN OPTIONS)

Date: August 26, 1997
Creator: EYSSA, Y. M.; WALSH, R. P.; MILLER, J. R.; MILLER, G. E.; PERNAMBUCO-WISE, P.; BIRD, M. D. et al.
Description: No abstract prepared.
Contributing Partner: UNT Libraries Government Documents Department
2 Letters from concerned citizens in response to the recommendation regarding the Defense Office of Hearings and Appeals in Fort Meade

2 Letters from concerned citizens in response to the recommendation regarding the Defense Office of Hearings and Appeals in Fort Meade

Date: July 30, 2005
Creator: unknown
Description: Community Correspondence - 2 Letters from concerned citizens in response to the recommendation regarding the Defense Office of Hearings and Appeals in Fort Meade
Contributing Partner: UNT Libraries Government Documents Department