Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Laser Diagnostics and Modeling of Plasma Assisted CVD. Final Technical Report
Author: Plasma and Laser Processing of Materials
Author: Kamleshwar UpadhyaPublisher:
ISBN:
Category : Finishes and finishing
Languages : en
Pages : 400
Book Description
The principal purpose of the conference on which this book was based was to provide a state of the art review of plasma assisted PVD, PACVD and laser enhanced CVD processes through papers dealing with basic fundamentals of plasma and laser assisted technology and also in depth papers related to continuing research on synthesis of metastable compounds.
Modeling and Laser Diagnostic Experiments in Laser-assisted Chemical Vapor Deposition
Author: David Clinton SkoubyPublisher:
ISBN:
Category :
Languages : en
Pages : 332
Book Description
Laser Diagnostics of Reacting Molecular Plasmas for Plasma Assisted Combustion Applications
Author: Caroline WintersPublisher:
ISBN:
Category : Aerospace engineering
Languages : en
Pages : 228
Book Description
This work has produced extensive sets of new data on low-temperature plasma-assisted fuel oxidation in hydrogen-oxygen-argon and hydrocarbon-oxygen-argon mixtures. The measurements have been made in two different plasma flow reactors, at an initial temperature of 500 K and pressures ranging from 300 Torr to 700 Torr. In both reactors, the plasma is generated by a high peak voltage, ns pulse discharge, operated at high pulse repetition rates (up to 20 kHz). Metastable Ar atom number density distributions in the discharge afterglow are measured by Tunable Diode Laser Absorption Spectroscopy (TDLAS), and used to characterize plasma uniformity. Temperature in the discharge-excited reacting flow is measured by Rayleigh scattering. Two-photon Absorption Laser Induced Fluorescence (TALIF) is used to measured absolute H and O atom number densities. The results are compared with predictions of a kinetic model analyzing reaction kinetics of excited species and radicals generated by the plasma at low temperatures and high pressures. The modeling predictions show good agreement with the data, with the exception of fuel-limited mixtures, when nearly all fuel available in the mixture of reactants is oxidized in the discharge. Kinetic modeling analysis identified dominant processes of generation and decay of atomic and radical species in the discharge and in the afterglow. At the present low-temperature conditions, the effect of chain branching reactions on plasma-assisted fuel oxidation kinetics is insignificant.
LDRD Final Report
Author: M. R. DorrPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The goal of this project was to investigate the utility of parallel adaptive mesh refinement (AMR) in the simulation of laser plasma interaction (LPI). The scope of work included the development of new numerical methods and parallel implementation strategies. The primary deliverables were (1) parallel adaptive algorithms to solve a system of equations combining plasma fluid and light propagation models, (2) a research code implementing these algorithms, and (3) an analysis of the performance of parallel AMR on LPI problems. The project accomplished these objectives. New algorithms were developed for the solution of a system of equations describing LPI. These algorithms were implemented in a new research code named ALPS (Adaptive Laser Plasma Simulator) that was used to test the effectiveness of the AMR algorithms on the Laboratory's large-scale computer platforms. The details of the algorithm and the results of the numerical tests were documented in an article published in the Journal of Computational Physics [2]. A principal conclusion of this investigation is that AMR is most effective for LPI systems that are ''hydrodynamically large'', i.e., problems requiring the simulation of a large plasma volume relative to the volume occupied by the laser light. Since the plasma-only regions require less resolution than the laser light, AMR enables the use of efficient meshes for such problems. In contrast, AMR is less effective for, say, a single highly filamented beam propagating through a phase plate, since the resulting speckle pattern may be too dense to adequately separate scales with a locally refined mesh. Ultimately, the gain to be expected from the use of AMR is highly problem-dependent. One class of problems investigated in this project involved a pair of laser beams crossing in a plasma flow. Under certain conditions, energy can be transferred from one beam to the other via a resonant interaction with an ion acoustic wave in the crossing region. AMR provides an effective means of achieving adequate resolution in the crossing region while avoiding the expense of using the same fine grid everywhere, including the region between the beams where no LPI occurs. We applied ALPS to a suite of problems modeling crossed beam experiments performed on the Omega laser at the University of Rochester. Our simulations contributed to the theoretical interpretation of these experiments, which was recently published in Physical Review Letters [4]. This project has advanced the Laboratory's computational capabilities in the area of AMR algorithms and their application to LPI problems. The knowledge gained and software developed will contribute to the computational tools available for use in the design and interpretation of experiments to be performed at the National Ignition Facility (NIF) in support of Laboratory missions in stockpile stewardship, energy research and high energy density science.
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