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Challenges for Plasma Diagnostics in a Next Step Device (FIRE) (open access)

Challenges for Plasma Diagnostics in a Next Step Device (FIRE)

The physics program of any next-step tokamak such as FIRE [Fusion Ignition Research Experiment] sets demands for plasma measurement which are at least as comprehensive as on present tokamaks, with the additional capabilities needed for control of the plasma and for understanding the effects of the alpha-particles. The diagnostic instrumentation must be able to provide the fine spatial and temporal resolution required for the advanced tokamak plasma scenarios. It must also be able to overcome the effects of neutron- and gamma-induced electrical noise in ceramic components or detectors, and fluorescence and absorption in optical components. There are practical engineering issues of minimizing radiation streaming while providing essential diagnostic access to the plasma. Many diagnostics will require components at or close to the first wall, e.g., ceramics and MI cable for magnetic diagnostics and mirrors for optical diagnostics; these components must be mounted to operate, and survive, i n fluxes which require special material selection. A better set of diagnostics of alpha-particles than that available for the TFTR [Tokamak Fusion Test Reactor] is essential; it must be qualified well before moving into D-T [deuterim-tritium] experiments. A start has been made to assessing the potential implementation of key diagnostics for the FIRE …
Date: January 28, 2002
Creator: Young, Kenneth M.
System: The UNT Digital Library
Boronization on NSTX using Deuterated Trimethylboron (open access)

Boronization on NSTX using Deuterated Trimethylboron

Boronization on the National Spherical Torus Experiment (NSTX) has proved to be quite beneficial with increases in confinement and density, and decreases in impurities observed in the plasma. The boron has been applied to the interior surfaces of NSTX, about every 2 to 3 weeks of plasma operation, by producing a glow discharge in the vacuum vessel using deuterated trimethylboron (TMB) in a 10% mixture with helium. Special NSTX requirements restricted the selection of the candidate boronization method to the use of deuterated boron compounds. Deuterated TMB met these requirements, but is a hazardous gas and special care in the execution of the boronization process is required. This paper describes the existing GDC, Gas Injection, and Torus Vacuum Pumping System hardware used for this process, the glow discharge process, and the automated control system that allows for remote operation to maximize both the safety and efficacy of applying the boron coating. The administrative requirements and the detailed procedure for the setup, operation and shutdown of the process are also described.
Date: January 28, 2002
Creator: Blanchard, W.R.; Gernhardt, R.C.; Kugel, H.W. & LaMarche, P.H.
System: The UNT Digital Library
High Heat Flux Interactions and Tritium Removal from Plasma Facing Components by a Scanning Laser (open access)

High Heat Flux Interactions and Tritium Removal from Plasma Facing Components by a Scanning Laser

A new technique for studying high heat flux interactions with plasma facing components is presented. The beam from a continuous wave 300 W neodymium laser was focused to 80 W/mm2 and scanned at high speed over the surface of carbon tiles. These tiles were previously used in the TFTR [Tokamak Fusion Test Reactor] inner limiter and have a surface layer of amorphous hydrogenated carbon that was codeposited during plasma operations. Laser scanning released up to 84% of the codeposited tritium. The temperature rise of the codeposit on the tiles was significantly higher than that of the manufactured material. In one experiment, the codeposit surface temperature rose to 1,770 C while for the same conditions, the manufactured surface increased to only 1,080 C. The peak temperature did not follow the usual square-root dependence on heat pulse duration. Durations of order 100 ms resulted in brittle destruction and material loss from the surface, while a duration of approximately 10 ms showed minimal change. A digital microscope imaged the codeposit before, during, and after the interaction with the laser and revealed hot spots on a 100-micron scale. These results will be compared to analytic modeling and are relevant to the response of plasma …
Date: January 28, 2002
Creator: Skinner, C. H.; Gentile, C. A. & Hassanein, A.
System: The UNT Digital Library
Status of the Experimental Physics and Industrial Control System at NSTX (open access)

Status of the Experimental Physics and Industrial Control System at NSTX

The NSTX achieved first plasma in 1999. The Experimental Physics and Industrial Control System (EPICS) is used to provide data-integration services for monitoring and control of all NSTX engineering subsystems. EPICS is a set of software initially developed at U.S. DOE laboratories. It is currently used and maintained through a global collaboration of hundreds of scientists and engineers. This paper will relate some of our experiences using and supporting the EPICS software. Topics include reliability and maintainability, lessons learned, recently added engineering subsystems, new EPICS software tools, and a review of our first EPICS software upgrade. Steps to modernize the technical infrastructure of EPICS to ensure effective support for NSTX will also be described.
Date: January 28, 2002
Creator: Sichta, P. & Dong, J.
System: The UNT Digital Library
The NSTX Trouble Reporting System (open access)

The NSTX Trouble Reporting System

An online Trouble Reporting System (TRS) has been introduced at the National Spherical Torus Experiment (NSTX). The TRS is used by NSTX operators to report problems that affect NSTX operations. The purpose of the TRS is to enhance NSTX reliability and maintainability by identifying components, occurrences, and trends that contribute to machine downtime. All NSTX personnel have access to the TRS. The user interface is via a web browser, such as Netscape or Internet Explorer. This web-based feature permits any X-terminal, PC, or MAC access to the TRS. The TRS is based upon a trouble reporting system developed at the DIII-D Tokamak, at General Atomics Technologies. This paper will provide a detailed description of the TRS software architecture, user interface, MS SQL server interface and operational experiences. In addition, sample data from the TRS database will be summarized and presented.
Date: January 28, 2002
Creator: Sengupta, S. & Oliaro, G.
System: The UNT Digital Library
Education Finance Incentive Grants Under ESEA Title I (open access)

Education Finance Incentive Grants Under ESEA Title I

This report estimates the amount of funds that will be awarded to each state according to the formula, and also describes how the grants reward states that have education finance systems with characteristics favored by the formula.
Date: January 28, 2002
Creator: Smole, David P.
System: The UNT Digital Library
Lattice Boltzmann Modeling of Micro-fluidic Devices (open access)

Lattice Boltzmann Modeling of Micro-fluidic Devices

The results to date do indeed show that the lattice Boltzmann method accurately solves relevant, non-trivial flow problems. The parallelization of both the fluid and the mobile species in flow has enhanced this capability such that it is useful for solving relevant problems in a timely fashion. The initial studies of stationary or capture species revealed evidence of hydrodynamic screening between upstream and downstream particles. Numerical studies reveal that the critical length for which the test particle is hydrodynamically decoupled from upstream and downstream particles is on the order of 30 sphere radii. For mobile species, the LB capability was shown to be naturally suited for predicting the hydrodynamic lift phenomenon (inertial lift). A conversion factor was developed based on scaling arguments to include relevant forces generated by external fields. Using this conversion, an analytic solution for the Dielectrophoretic force was included into the LB capability which enabled the study of Dielectrophoretic particle capture. The Non-Newtonian enhancements have expanded the applicability of the LB capability to more physical systems. Specifically, with the bead-n-spring representation of macromolecules researchers will be able to study chain dynamics in micro-, physiological and Bio-MEMS environments. Furthermore, the ability to capture the shear thinning behavior, without …
Date: January 28, 2002
Creator: Clague, D S
System: The UNT Digital Library
Patent Quality and Public Policy: Issues for Innovative Firms in Domestic Markets (open access)

Patent Quality and Public Policy: Issues for Innovative Firms in Domestic Markets

None
Date: January 28, 2002
Creator: unknown
System: The UNT Digital Library
Behavior of Rare Earth Element In Geothermal Systems; A New Exploration/Exploitation Tool (open access)

Behavior of Rare Earth Element In Geothermal Systems; A New Exploration/Exploitation Tool

The goal of this four-year project was to provide a database by which to judge the utility of the rare earth elements (REE) in the exploration for and exploitation of geothermal fields in the United States. Geothermal fluids from hot springs and wells have been sampled from a number of locations, including: (1) the North Island of New Zealand (1 set of samples); (2) the Cascades of Oregon; (3) the Harney, Alvord Desert and Owyhee geothermal areas of Oregon; (4) the Dixie Valley and Beowawe fields in Nevada; (5) Palinpion, the Philippines: (6) the Salton Sea and Heber geothermal fields of southern California; and (7) the Dieng field in Central Java, Indonesia. We have analyzed the samples from all fields for REE except the last two.
Date: January 28, 2002
Creator: Wood, Scott A.
System: The UNT Digital Library
Microinstability Studies for the Large Helical Device (open access)

Microinstability Studies for the Large Helical Device

Fully kinetic assessments of the stability properties of toroidal drift modes have been obtained for cases for the Large Helical Device (LHD). This calculation employs the comprehensive linear microinstability code FULL, as recently extended for nonaxisymmetric systems. The code retains the important effects in the linearized gyrokinetic equation, using the lowest-order ''ballooning representation'' for high toroidal mode number instabilities in the electrostatic limit. These effects include trapped particles, FLR, transit and bounce and magnetic drift frequency resonances, etc., for any number of plasma species. Results for toroidal drift waves destabilized by trapped electrons and ion temperature gradients are presented, using numerically-calculated three-dimensional MHD equilibria. These are reconstructed from experimental measurements. Quasilinear fluxes of particles and energy for each species are also calculated. Pairs of LHD discharges with different magnetic axis positions and with and without pellet injection are compared.
Date: January 28, 2002
Creator: Rewoldt, G.; Ku, L. P.; Tang, W. M.; Sugama, H.; Nakajima, N.; Watanabe, K. Y. et al.
System: The UNT Digital Library
Magnetized Turbulent Dynamo in Protogalaxies (open access)

Magnetized Turbulent Dynamo in Protogalaxies

The prevailing theory for the origin of cosmic magnetic fields is that they have been amplified to their present values by the turbulent dynamo inductive action in the protogalactic and galactic medium. Up to now, in calculation of the turbulent dynamo, it has been customary to assume that there is no back reaction of the magnetic field on the turbulence, as long as the magnetic energy is less than the turbulent kinetic energy. This assumption leads to the kinematic dynamo theory. However, the applicability of this theory to protogalaxies is rather limited. The reason is that in protogalaxies the temperature is very high, and the viscosity is dominated by magnetized ions. As the magnetic field strength grows in time, the ion cyclotron time becomes shorter than the ion collision time, and the plasma becomes strongly magnetized. As a result, the ion viscosity becomes the Braginskii viscosity. Thus, in protogalaxies the back reaction sets in much earlier, at field strengths much lower than those which correspond to field-turbulence energy equipartition, and the turbulent dynamo becomes what we call the magnetized turbulent dynamo. In this paper we lay the theoretical groundwork for the magnetized turbulent dynamo. In particular, we predict that the …
Date: January 28, 2002
Creator: Malyshkin, Leonid & Kulsrud, Russell M.
System: The UNT Digital Library
Upgrade to the Tritium Remote Control and Monitoring System for TFTR D and D (open access)

Upgrade to the Tritium Remote Control and Monitoring System for TFTR D and D

Since 1988, the Tritium Remote Control and Monitoring System (TRECAMS) has performed crucial functions in support of D-T [deuterium-tritium] operations of the Tokamak Fusion Test Reactor (TFTR) at the Princeton Plasma Physics Laboratory (PPPL). Although plasma operations on TFTR were completed in 1997, the need for TRECAMS continued. During this period TRECAMS supported the TFTR tritium systems, the TFTR's Shutdown and Safing phase, and the TFTR Decontamination and Decommissioning (D and D) project. The most critical function of the TRECAMS in the post-TFTR era has been to provide a real-time indication of the airborne tritium levels in the tritium areas and the (HVAC) stacks. TRECAMS is a critical tool in conducting safe TFTR D and D tritium-line breaks and other tritium-related work activities. Beginning in 1998, the failure rate of the system's hardware sharply increased. Furthermore, the specialized knowledge required to maintain the original software and hardware was diminishing. It soon became apparent that a failure of the TRECAMS could significantly impact the TFTR D and D project's cost and schedule. To preclude this, the TRECAMS hardware and software was upgraded in the year 2000 to use modern components. This paper will describe that successful upgrade, including a review of …
Date: January 28, 2002
Creator: Sichta, P.; Oliaro, G. & Sengupta, S.
System: The UNT Digital Library
Characterization of Mixed Wettability at Different Scales and its Impact on Oil Recovery Efficiency (open access)

Characterization of Mixed Wettability at Different Scales and its Impact on Oil Recovery Efficiency

The objectives of this project was to: (1) quantify the pore scale mechanisms that determine the wettability state of a reservoir, (2) study the effect of crude oil, brine and mineral compositions in the establishment of mixed wet states, (3) clarify the effect of mixed - wettability on oil displacement efficiency in waterfloods, (4) develop a new tracer technique to measure wettability, fluid distributions, residual saturation's and relative permeabilities, and (5) develop methods for properly incorporating wettability in up-scaling from pore to core to reservoir scales.
Date: January 28, 2002
Creator: Sharma, Mukul M. & Hirasaki, George J.
System: The UNT Digital Library
Enhanced Mode Conversion of Thermally Emitted Electron Bernstein Waves (EBW)to Extraordinary Mode (open access)

Enhanced Mode Conversion of Thermally Emitted Electron Bernstein Waves (EBW)to Extraordinary Mode

In the CDX-U spherical torus, approximately 100% conversion of thermal EBWs to X-mode has been observed by controlling the electron density scale length (Ln) in the conversion region with a local limiter outside the last closed flux surface. The radiation temperature profile agrees with Thomson scattering electron temperature data. Results are consistent with theoretical calculations of conversion efficiency using measured Ln. By reciprocity of the conversion process, prospects for efficient coupling in EBW heating and current drive scenarios are strongly supported.
Date: January 28, 2002
Creator: Jones, B.; Efthimion, P. C.; Taylor, G.; Munsat, T.; Wilson, J. R.; Hosea, J. C. et al.
System: The UNT Digital Library
Land and Water Conservation Fund: Current Status and Issues (open access)

Land and Water Conservation Fund: Current Status and Issues

This report provides the current status and issues of land and water conservation fund.
Date: January 28, 2002
Creator: Zinn, Jeffrey
System: The UNT Digital Library
Development of a Detector to Measure the Angular Dependence of the Cosmic Ray Induced Neutron Background Flux at Ground Level (open access)

Development of a Detector to Measure the Angular Dependence of the Cosmic Ray Induced Neutron Background Flux at Ground Level

The detection of low intensity sources of radiation in containers is of particular interest for arms control, non-proliferation and nuclear smuggling activities. Attempts to procure and smuggle nuclear materials that could be used in terrorist activities have been well documented in recent years. These incidents have included fissile materials such, as plutonium and uranium, as well as medical and industrial isotopes that could be used in a Radiation Dispersal Device. The vast majority of these incidents have been discovered through human intelligence work due to the difficulty of using radiation monitoring. The detection of radiation sources in well-shielded containers presents a difficult technological challenge. Few neutrons and gamma rays may escape from the container and these may be obscured by the naturally occurring background. The world in general is a radioactive environment. Many elements in the earth's crust, as well as in common plants and building materials, emit a constant stream of radiation. In fact the ultimate limit on the detection of hidden sources is often the background level at the location of interest. It has long been understood that knowledge of the directionality of this background can be used to improve the signal/noise ratio in detectors used for these …
Date: January 28, 2002
Creator: Morgan, J. F.; Gosnell, T B; Luke, S J; Archer, D E; Lochner, R T; Frank, I M et al.
System: The UNT Digital Library
Homeland Security: Coast Guard Operations - Background and Issues for Congress (open access)

Homeland Security: Coast Guard Operations - Background and Issues for Congress

This report provides information about the Background and Issues for Congress on Homeland Security Coast Guard Operations which is a military service and a branch of the armed forces,within the navy upon the declaration of war or when President directs until the president by executive orders it back to DHS
Date: January 28, 2002
Creator: O'Rourke, Ronald
System: The UNT Digital Library
Pipeline Safety: Federal Program and Reauthorization Issues (open access)

Pipeline Safety: Federal Program and Reauthorization Issues

None
Date: January 28, 2002
Creator: Rothberg, Paul F. & Hassan, Hussein D.
System: The UNT Digital Library
Rural Education: Legislative Initiatives (open access)

Rural Education: Legislative Initiatives

Congressional Research Service (CRS) report for Congress entailing legislative initiatives in regards to rural education . Topics include, new legislation, provisions under the new rural education achievement program under the reauthorized ESEA, implementation, etc..
Date: January 28, 2002
Creator: Stedman, James B. & Apling, Richard N.
System: The UNT Digital Library
Land and Water Conservation Fund: Current Status and Issues (open access)

Land and Water Conservation Fund: Current Status and Issues

None
Date: January 28, 2002
Creator: Zinn, Jeffrey A.
System: The UNT Digital Library
Permanent Normal Trade Relations (PNTR) Status for Russia and U.S.-Russian Economic Ties (open access)

Permanent Normal Trade Relations (PNTR) Status for Russia and U.S.-Russian Economic Ties

None
Date: January 28, 2002
Creator: Cooper, William H.
System: The UNT Digital Library
SSI Income and Resource Limits: A Fact Sheet (open access)

SSI Income and Resource Limits: A Fact Sheet

None
Date: January 28, 2002
Creator: Lake, Jennifer E.
System: The UNT Digital Library