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Neutral-fueling pressure measurements and modeling near the plasma edge in TMX-U

Description: Large variations in pressure from external gas-fueling sources and from plasma-induced wall reflux along the TMX-U plasma have been observed. These pressure variations can produce locally high neutral density in the plasma, which strongly affects the plasma parameters. These local pressure measurements include data from a newly installed neutral-pressure diagnostic system of fast magnetron gauges. The plasma-induced warm-wall reflux has been observed to be primarily HD and H/sub 2/ as opposed t… more
Date: December 3, 1984
Creator: Pickles, W.L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Thermal instabilities in the edge region of reversed-field pinches

Description: Thermal stability of the edge region of reversed-field pinch configurations is analyzed within the context of a two-fluid model. Two major sources of instability are identified in combination with a parallel electric field: either an electron temperature gradient and/or a density gradient that leads to rapid growth (of several to many ohmic heating rates) over a region of several millimeters around the mode-rational surfaces in the edge region. The basic signature of both instabilities is elect… more
Date: April 1, 1984
Creator: Goedert, J. & Mondt, J.P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Application of toroidal multipoles to facilitate tokamak reactor studies

Description: A method of calculating the vacuum magnetic flux for plasma equilibrium over a range of aspect ratio A and major radius R is presented. Toroidal multipoles are used to fit the vacuum flux for a set of reference equilibria and the fitted moments are then used to parametrize the flux over the design space in A and R. An example is given in which the equilibrium flux for a D-shaped tokamak plasma is predicted and compared with the actual equilibrium code vacuum flux.
Date: May 1, 1984
Creator: Ehrhardt, A. B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Transport of neutral atoms and molecules in TFCX

Description: The distribution of neutrals in the proposed reactor TFCX has been modeled by the 3-D Monte Carlo neutral transport code DEGAS, which has been run in conjunction with the 1-1/2-D time-dependent plasma transport code WHIST. The former code contains the best available treatment of neutral-particle physics, including a selection of wall reflection models. The latter code has a comprehensive set of plasma transport coefficients, an MHD equilibrium package, and provision for source terms such as tho… more
Date: September 1, 1984
Creator: Boley, C. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Magnetic fusion energy plasma interactive and high heat flux components. Volume I. Technical assessment of the critical issues and problem areas in the plasma materials interaction field

Description: A technical assessment of the critical issues and problem areas in the field of plasma materials interactions (PMI) in magnetic fusion devices shows these problems to be central for near-term experiments, for intermediate-range reactor devices including D-T burning physics experiments, and for long-term reactor machines. Critical technical issues are ones central to understanding and successful operation of existing and near-term experiments/reactors or devices of great importance for the long … more
Date: January 1, 1984
Creator: Conn, R. W.; Gauster, W. B.; Heifetz, D.; Marmar, E. & Wilson, K. L. (eds.)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Impurity Control Test Facility (ICTF) for the study of fusion reactor plasma/edge materials interactions

Description: A test facility for investigating many of the impurity control issues associated with the interactions of materials with the plasma edge is outlined. Analysis indicates that the plasma edge conditions expected in TFCX, INTOR, etc. can be readily produced at the end cells of an rf stabilized mirror, similar in some respects to the Phaedrus device at the University of Wisconsin. A steady-state, Impurity Control Test Facility (ICTF) based on such a mirror device is expected to produce a plasma wit… more
Date: May 1, 1984
Creator: Brooks, J. N.; Mattas, R. F.; Ehst, D. A.; Boley, C. D. & Hershkowitz, N.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Negative ion formation due to hydrogen plasma surface interaction

Description: Negative ions can be produced by a desorption process when energetic positive hydrogen ions impinge on the surface of reactor walls. The relative yield of different negative ions generated from various surface materials (such as Mo, Pt, Pd, Rh, Cu, Ta, Au, C, TiC and stainless-steel) have been compared in a multicusp plasma source. The negative ions generated are self-extracted from the source, and are identified by a mass spectrometer. The total negative ion current is measured by a Faraday cu… more
Date: May 1, 1984
Creator: Leung, K. N. & Ehlers, K. W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Design and Analysis of a Low Edge Temperature Divertor for INTOR

Description: A low plasma edge temperature regime has been proposed for the INTOR divertor in order to minimize erosion on the collector plate. We have examined the design and lifetime issues of a divertor plate operating in such a regime. These issues include the choice of materials, erosion due to sputtering and disruptions, thermal response, and tritium permeation. We have concluded that a tungsten coated, copper substrate plate offers the possibility of low erosion coupled with good thermal properties. … more
Date: May 1, 1984
Creator: Brooks, J. N.; Mattas, R. F.; Hassanein, A. M. & Baskes, M. I.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Magnetic Fusion Energy Plasma Interactive and High Heat Flux Components. Volume II. Technical Assessment of the Critical Issues and Problem Areas in High Heat Flux Materials and Component Development

Description: A technical assessment of the critical issues and problem areas for high heat flux materials and components (HHFMC) in magnetic fusion devices shows these problems to be of critical importance for the successful operation of near-term fusion experiments and for the feasibility and attractiveness of long-term fusion reactors. A number of subgroups were formed to assess the critical HHFMC issues along the following major lines: (1) source conditions, (2) systems integration, (3) materials and pro… more
Date: June 1, 1984
Creator: Abdou, M. A.; Boyd, R. D.; Easor, J. R.; Gauster, W. B.; Gordon, J. D.; Mattas, R. F. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Edge diagnostics for tandem mirror machines

Description: The edge plasma in a tandem mirror machine shields the plasma core from cold neutral gas and impurities. A variety of diagnostics are used to measure the fueling, shielding, and confinement of the edge plasma in both the end plug and central cell regions. Fast ion gauges and residual gas analyzers measure the gas pressure and composition outside of the plasma. An array of Langmuir probes is used to measure the electron density and temperature. Extreme ultraviolet (euv) and visible spectroscopy … more
Date: September 14, 1984
Creator: Allen, S. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

New fluctuation phenomena in the H-mode regime of PDX tokamak plasmas

Description: A new kind of quasi-coherent fluctuation is observed near the edge of plasmas in the PDX tokamak during H-mode operation. (The H-mode occurs in neutral beam heated divertor plasmas and is characterized by improved energy containment as well as large density and temperature gradients near the plasma edge.) These fluctuations are evidenced as VUV and density fluctuation bursts at well-defined frequencies (..delta omega../..omega.. less than or equal to 0.1) in the frequency range between 50 and 1… more
Date: May 1, 1984
Creator: Slusher, R. E.; Surko, C. M.; Valley, J. F.; Crowley, T.; Mazzucato, E. & McGuire, K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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