Parametric Instabilities in Laser/Matter Interaction: From Noise Levels to Relativistic Regimes (open access)

Parametric Instabilities in Laser/Matter Interaction: From Noise Levels to Relativistic Regimes

The purpose of this LDRD was the study of parametric instabilities on a laser-produced plasma, addressing crucial issues affecting the coupling between the laser and the plasma. We have made very good progress during these three years, in advancing our understanding in many different fronts. Progress was made in both theoretical and experimental areas. The coupling of high-power laser light to a plasma through scattering instabilities is still one of the most complex processes in laser-plasma interaction physics. In spite of the relevance of these parametric processes to inertial confinement fusion (ICF) and all other situations where a high-power laser beam couples to a plasma, many aspects of the interaction remain unexplained, even after many years of intensive experimental and theoretical efforts. Important instabilities under study are stimulated Brillouin scattering (SBS), stimulated Raman scattering (SRS), and the Langmuir decay instability (LDI). The study of these instabilities is further complicated by the competition and interplay between them, and, in the case of ICF, by the presence of multiple overlapping interaction beams. Stimulated Brillouin scattering consists of the decay of the incident electromagnetic (EM) wave into a scattered EM wave and an ion acoustic wave (IAW). Similarly, SRS consists of the decay …
Date: February 11, 1999
Creator: Baldis, H. A.; Kruer, W. L. & Labaune, C. L.
Object Type: Report
System: The UNT Digital Library
The kinetic tandem concept: theory and computer simulations of the potential barriers (open access)

The kinetic tandem concept: theory and computer simulations of the potential barriers

The Kinetic Tandem fusion plasma confinement concept is a member of the class of open magnetic confinement systems whose magnetic topology is that of a tube of magnetic flux open at both ends. In open-ended systems the central problem is that of limiting the rate of plasma losses out the ends. In a conventional tandem mirror system end-plugging is accomplished by the generation of positive potential barriers within special short mirror cells located at each end of a long central confinement cell. The kinetic tandem concept accomplishes the same end result by employing dynamic effects, but without the necessity of special end cells. The field employed in the kinetic tandem is a simple axially symmetric solenoidal field whose intensity tapers to low values at the ends. Since the field line curvature is everywhere positive such a field is stabilizing for MHD interchange modes. Into each end are injected ion beams that are aimed nearly parallel to the field line direction. The ions from these beams then are radially compressed, stopped, and reflected back by magnetic mirror action in climbing up the magnetic gradient. In this way ion density peaks are formed between which the plasma is to be confined. As …
Date: February 11, 1999
Creator: Byers, J A & Post, R F
Object Type: Report
System: The UNT Digital Library
Risk Analysis and Decision-Making Software Package (1997 Version) User Manual (open access)

Risk Analysis and Decision-Making Software Package (1997 Version) User Manual

This manual provides instructions for using the U.S. Department of Energy's (DOE) risk analysis and decision making software (1997 version) developed at BDM Petroleum Technologies by BDM-Oklahoma, Inc. for DOE, under contract No. DE-AC22-94PC91OO8. This software provides petroleum producers with a simple, handy tool for exploration and production risk analysis and decision-making. It collects useful risk analysis tools in one package so that users do not have to use several programs separately. The software is simple to use, but still provides many functions. The 1997 version of the software package includes the following tools: (1) Investment risk (Gambler's ruin) analysis; (2) Monte Carlo simulation; (3) Best fit for distribution functions; (4) Sample and rank correlation; (5) Enhanced oil recovery method screening; and (6) artificial neural network. This software package is subject to change. Suggestions and comments from users are welcome and will be considered for future modifications and enhancements of the software. Please check the opening screen of the software for the current contact information. In the future, more tools will be added to this software package. This manual includes instructions on how to use the software but does not attempt to fully explain the theory and algorithms used to …
Date: February 11, 1999
Creator: Chung, F. T. H.
Object Type: Report
System: The UNT Digital Library
Large Area Deposition of Field Emission Cathodes for Flat Panel Displays (open access)

Large Area Deposition of Field Emission Cathodes for Flat Panel Displays

The convention for field emission cathode (FEC) synthesis involves coating with a very-high tolerance in thickness uniformity using a planetary substrate fixture and a large source-to-substrate separation. New criteria for a deposition process must facilitate a reduction in the operating voltage by increasing the density of emitters through a reduction of cathode size and spacing. The objective of scaling the substrate size from small (less than 30 cm{sup 2}) to large (greater than 500 cm{sup 2}) areas further compounds manufacturing requirements to a point beyond that easily obtained by modifications to the convention for FEC deposition. A new patented approach to design, assemble, and operate a coating system enables FEC deposition over large areas through process control of source divergence coupled to incremental substrate positioning.
Date: February 11, 1999
Creator: Ferreira, J.; Hayes, J.; Jankowski, Alan Frederic & Morse, J.
Object Type: Article
System: The UNT Digital Library
Environmental Assessment and Finding of No Significant Impact: Widening Trench 36 of the 218-E-12B Low-Level Burial Ground, Hanford Site, Richland, Washington (open access)

Environmental Assessment and Finding of No Significant Impact: Widening Trench 36 of the 218-E-12B Low-Level Burial Ground, Hanford Site, Richland, Washington

This environmental assessment was prepared to assess potential environmental impacts associated with the proposed action to widen and operate unused Trench 36 in the 218-E-12B Low-Level Burial Ground for disposal of low-level waste. Information contained herein will be used by the Manager, U.S. Department of Energy, Richland Operations Office, to determine if the Proposed Action is a major federal action significantly affecting the quality of the human environment. If the Proposed Action is determined to be major and significant, an environmental impact statement will be prepared. If the Proposed Action is determined not to be major and significant, a Finding of No Significant Impact will be issued and the action may proceed. Criteria used to evaluate significance can be found in Title 40, Code of Federal Regulations 1508.27. This environmental assessment was prepared in compliance with the ''National Environmental Policy Act of1969'', as amended, the Council on Environmental Quality Regulations for Implementing the Procedural Provisions of ''National Environmental Policy Act'' (Title 40, Code of Federal Regulations 1500-1508), and the U.S. Department of Energy Implementing Procedures for ''National Environmental Polio Act'' (Title 10, Code of Federal Regulations 1021). The following is a description of each section of this environmental assessment. (1) …
Date: February 11, 1999
Creator: unknown
Object Type: Report
System: The UNT Digital Library