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in subjects: "Plasma Diagnostics"

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The multipulse Thomson scattering diagnostic on the DIII-D tokamak

This paper describes the design and operation of a 40-spatial channel Thomson scattering system that uses multiple 20 Hz Nd:YAG lasers to measure the electron temperature and density profiles periodically throughout an entire plasma discharge. Interference filter polychromators disperse the scattered light which is detected by silicon avalanche photodiodes. The measurable temperature range from 10 eV to 20 keV and the minimum detectable density is about 2 {times} 10{sup 18} m{sup {minus}3}. Las… more

Date: September 1, 1991

Creator: Carlstrom, T. N.; Campbell, G. L.; DeBoo, J. C.; Evanko, R. G.; Evans, J.; Greenfield, C. M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The interpretation of reflectometry measurements of plasma fluctuations

Wave reflections from density fluctuations with magnitudes and frequencies typical of drift waves have been investigated. Both drift waves and the reflected phase and amplitude depend on the density gradient scale length, and this common feature implies that both the angular deviation of a normally propagating wave and the phase change on reflection are of order unity. Thus the surface will always appear rough'' and amplitude variations will always be large. For smaller amplitude waves numerica… more

Date: October 1, 1991

Creator: Bretz, N.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Application of optical fluctuation diagnostics to transport studies in high temperature tokamak plasmas

First data was obtained from the TFTR BES system in May 1990, after the prototype 4-channel system with photomultiplier detectors from PBX-M was transferred to the TFTR Hot Cell. The system was expanded to 16 spatial channels during the Summer 1990 run period, and data of interest was obtained near the end of the run in October 1990. The most attention has been given to a radial profile data set obtained for an L-mode plasma condition in TFTR, where we characterized the nature of the long-wavel… more

Date: January 1, 1991

Creator: Fonck, R.J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Study of ICRF wave propagation and plasma coupling efficiency in a linear magnetic mirror device

Ion Cyclotron Range of Frequency (ICRF) wave propagation in an inhomogeneous axial magnetic field in a cylindrical plasma-vacuum system has historically been inadequately modelled. Previous works either sacrifice the cylindrical geometry in favor of a simpler slab geometry, concentrate on the resonance region, use a single mode to represent the entire field structure, or examine only radial propagation. This thesis performs both analytical and computational studies to model the ICRF wave-plasma… more

Date: July 1, 1991

Creator: Peng, S.Y.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Electron heating and confinemet measurements in EBT-S using Thomson scattering

Thomson scattering of ruby laser light was used to measure electron temperatures and densities in the ELMO Bumpy Torus-Scale (EBT-S) at Oak Ridge National Laboratory. The measurements were made primarily during May 1980, although some were taken during January 1980. The scattering system, which was designed for very low electron density measurements, features a 14-J ruby laser, a high-throughput spectrometer, and 15% quantum efficiency photomultipliers. The measured electron densities lie in th… more

Date: September 1, 1980

Creator: Bighel, L. & Cobble, J. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Performance study of the TFTR diagnostic neutral beam for active charge exchange measurements

A neutral beam source will be incorporated in the Tokamak Fusion Test Reactor (TFTR) charge exchange diagnostic to provide a time modulated, spatially localized enhancement of the charge exchange efflux. Two autonomous Charge Exchange Neutral Analyzer (CENA) systems are being designed for the TFTR. One system measures the plasma ion temperature along twelve vertical line-of-sight chords spaced approximately equidistantly across the torus minor diameter. The other system is dedicated primarily t… more

Date: June 1, 1980

Creator: Medley, S. S.; Goldston, R. J. & Towner, H. H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Radio chemistry as a diagnostic in laser fusion experiments

Nuclear chemistry techniques have been employed in an attempt to measure the density of high compression laser fusion targets. Radioactive /sup 28/Al atoms formed in the /sup 28/Si(n,p)/sup 28/Al reaction arising from the interaction of the 14 MeV neutrons with the silicon atoms in the glass microsphere have been counted at Lawrence Livermore Laboratory using a ..beta..-..gamma.. coincidence method. The detection system that is employed allows activities corresponding to 100 aluminum atoms to b… more

Date: November 1, 1977

Creator: Campbell, E.M.; Hicks, H.G.; Mead, W.C.; Glaros, S.S.; Coleman, L.W. & Laird, W.B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

MHD Coal-Fired Flow Facility. Quarterly technical progress report, January-March 1980

The University of Tennessee Space Institute (UTSI) reports on significant activity, task status, planned research, testing, development, and conclusions for the Magnetohydrodynamics (MHD) Coal-Fired Flow Facility (CFFF) and the Research and Development Laboratory. Although slowed by incessant rain during several days, work on the CFFF Bid Packages progressed to nearly 100 percent completion, excluding later punchlist items. On the quench system, the cyclone separator was delivered to UTSI, and … more

Date: May 30, 1980

Creator: Altstatt, M. C. & Attig, R.C. Baucum, W.E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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High beta capture and mirror confinement of laser produced plasmas. Semiannual report, April 1, 1977--September 30, 1977

The LITE research program is addressing two aspects of mirror confinement physics. ECRH heating of the confined LITE plasma is being investigated as a means for producing a local electrostatic well to trap cold ions within the plasma and provide DCLC stabilization without the energy drain effects obtained with a cold stabilizing stream. Concurrently, the heavy ion beam probe diagnostic being developed in LITE to experimentally measure the space potential within a minimum-B mirror plasma. During… more

Date: September 1, 1977

Creator: Haught, A.F.; Tomlinson, R.G. & Ard, W.B.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Recent beam probe measurements on EBT, TMX, and RENTOR

It is noted that beam probe systems can provide accurate, reliable measurments of plasma space potential and nf(T/sub e/). Over some temperature range, at least, it should be possible to separate n and T/sub e/ by measuring the multiple ionization reaction products. It is also an ideal diagnostic for studying fluctuations since it provides a simultaneous measurement of phi and nf(T/sub e/) from the same point in the plasma and the measurements are continuous in time. Measurements can be made qu… more

Date: June 1, 1980

Creator: Hickok, R. L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Time-resolved x-ray line diagnostics of laser-produced plasmas

We have examined the underdense plasma conditions of laser irradiated disks using K x-rays from highly ionized ions. A 900 ps laser pulse of 0.532 ..mu..m light is used to irradiate various Z disks which have been doped with low concentrations of tracer materials. The tracers whose Z's range from 13 to 22 are chosen so that their K x-ray spectrum is sensitive to typical underdense plasma temperatures and densities. Spectra are measured using a time-resolved crystal spectrograph recording the ti… more

Date: January 1, 1982

Creator: Kauffman, R.L.; Matthews, D.L.; Kilkenny, J.D. & Lee, R.W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Laser diagnostics of H sup minus formation in a magnetic multicusp ion source

The populations of ground electronic state atomic hydrogen and ground electronic state, vibrationally-rotationally excited hydrogen molecules in a negative hydrogen ion source discharge have been measured using vacuum ultraviolet (VUV) laser absorption spectroscopy. Vibrational states up to v=8 and rotational levels as high as J=15 have been measured. The measurements have been made under a range of discharge conditions. The complete vibrational population distribution for v=1-8, J=1 has been o… more

Date: May 1, 1991

Creator: Young, A. T.; Chen, P.; Kunkel, W. B.; Leung, K. N.; Li, C. Y. & Stutzin, G. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Design of neutron streak camera for fusion diagnostics

The D-T burn time for advanced laser-fusion targets is calculated to be very short, < 50 ps. We describe the design of a neutron streak camera of 16 ps resolving time that can be used to study the temporal history of fusion burn. The cathode of the neutron streak camera is sensitive to neutrons and is curved such that the difference in the neutron path lengths from a point source to various parts of the cathode is compensated by electron transit times within the streak tube. Thus the cathode ca… more

Date: June 1, 1982

Creator: Wang, C. L.; Kalibjian, R. & Singh, M. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Studies of Plasma Transport

This report discusses the charge-coupled device camera and other plasma diagnostic equipment used to measure plasma density and other plasma properties. (LSP)

Date: July 22, 1991

Creator: Malmberg, J. H.; O'Neil, T. M. & Driscoll, C. F.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Automated computer analysis of plasma-streak traces from SCYLLAC

An automated computer analysis technique that locates and references the approximate centroid of single- or dual-streak traces from the Los Alamos Scientific Laboratory SCYLLAC facility is described. The technique also determines the plasma-trace width over a limited self-adjusting region. The plasma traces are recorded with streak cameras on Polaroid film, then scanned and digitized for processing. The analysis technique uses scene segmentation to separate the plasma trace from a reference fid… more

Date: January 1, 1977

Creator: Whitman, R.L.; Jahoda, F.C. & Kruger, R.P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Simple measurement of line density

Energy line density, E/sub l/ = ..integral..(F/2)nk(T/sub e/ + T/sub i/)dA, has proved to be one of the easiest (and most critical) measurements made on the Scylla IV-P, 5-m linear theta pinch. A quantitative evaluation of end-stoppering techniques is made available by extracting the line energy containment time, tau/sub E/sub l//, from the time history of E/sub l/. To model E/sub l/(t) properly and, hence, determine the details of energy loss mechanisms (streaming and thermal conduction) requi… more

Date: February 1, 1978

Creator: Armstrong, W.T. & Siemon, R.E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Optical imaging diagnostics for fusion plasmas

Imaging diagnostics are used for spatially/emdash/and temporally/emdash/resolved quantitative measurements of plasma properties such as the ionization particle source, particle and energy loss, and impurity radiation in magnetically confined fusion plasmas. Diagnostics equipped with multi-element solid-state detectors (often with image intensifiers) are well suited to the environment of large fusion machines with high magnetic field and x-ray and neutron fluxes. We have both conventional (16msf… more

Date: April 1, 1988

Creator: Allen, S.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Polarization spectroscopy of tokamak plasmas

Measurements of polarization of spectral lines emitted by tokamak plasmas provide information about the plasma internal magnetic field and the current density profile. The methods of polarization spectroscopy, as applied to the tokamak diagnostic, are reviewed with emphasis on the polarimetry of motional Stark effect in hydrogenic neutral beam emissions. 25 refs., 7 figs.

Date: September 1, 1991

Creator: Wroblewski, D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Electrostatic turbulence and transport in the RFP edge

This thesis details measurements of electrostatic turbulence and transport in the Madison Symmetric Torus reversed field pinch. The electrostatic fluctuation levels are found to be large, with {tilde n}{sub e}/n{sub e} {approximately} 30%--55% and {tilde T}{sub e}/T{sub e} {approximately} 15%--40%. The frequency and wavenumber spectra are broad, with {Delta}n {approximately} 70--150 and {Delta}m {approximately} 3--6, and differ from measured magnetic fluctuation spectra. The transport inferred … more

Date: May 1, 1992

Creator: Spragins, C.W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Beam and viewing dump positioning inside TFTR for CTS alpha-particle diagnostics

A collective Thomson scattering (CTS) diagnostic system for localized measurement of energetic ions is being developed for TFTR. This system will use a 200KW, 56GHz gyrotron and a sensitive heterodyne receiver. In addition, a key element of this system will be beam and viewing dumps which are needed to minimize detection of stray gyrotron and ECE background radiation by the receiver system. It is the purpose of this study to determine the size and location of these dumps inside TFTR taking into… more

Date: July 15, 1991

Creator: Rhee, D.Y.; Woskov, P.P. (Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center); Ellis, R. & Park, H. (Princeton Univ., NJ (United States). Plasma Physics Lab.)

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Addition of bromine as a diagnostic gas to inertial confinement fusion target microspheres

Currently, direct fuel rho r measurements on Inertial Confinement Fusion (ICF) targets by neutron activation of the argon tracer gas mixed with the DT fuel would require a 100 fold increase in neutron yield. Bromine, on the other hand, has excellent properties for neutron activation analysis at neutron yields of 10two' to 10/sup 8/, when present at an internal pressure of from 0.1 to 0.2 atmospheres. Bromine addition is accomplished in a 2 furnace system using the dried-gel method of microspher… more

Date: August 22, 1980

Creator: Morrison, R. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Spectra in the 60 )angstrom) to 345 )angstrom) wavelength region of elements injected into the PLT tokamak

High resolution spectra of the elements Fe, Ni, Zn, Ge, Se, and Mo injected into the PLT tokamak were recorded by the 2-meter Schwob-Fraenkel soft X-ray multichannel spectrometer (SOXMOS). Spectra were recorded every 50 ms during the time before and after injection. The spectral lines of the injected element were very strong in the spectrum recorded immedately after injection, and the transition in the injected element were easily distinguished from the transitions in te intrinsic elements (C, … more

Date: March 1, 1988

Creator: Wouters, A.; Schwob, J.L.; Suckewer, S.; Seely, J.F.; Feldman, U. & Dave, J.H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Measurements of beat wave accelerated electrons in a toroidal plasma

Electrons are accelerated by large amplitude electron plasma waves driven by counter-propagating microwaves with a difference frequency approximately equal to the electron plasma frequency. Energetic electrons are observed only when the phase velocity of the wave is in the range 3v{sub e} < v{sub ph} < 7v{sub e} (v{sub ph} was varied 2v{sub e} < v{sub ph} < 10v{sub e}), where v{sub e} is the electron thermal velocity, (kT{sub e}/m{sub e}){sup {1/2}}. As the phase velocity increases, fewer elect… more

Date: June 1, 1992

Creator: Rogers, J.H. (Princeton Univ., NJ (United States). Plasma Physics Lab.) & Hwang, D.W. (California Univ., Davis, CA (United States). Dept. of Applied Science Lawrence Livermore National Lab., CA (United States))

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Maryland controlled fusion research program

In this paper, we summarize the technical progress in four major areas of tokamak research: (a) L/H transition and edge turbulence and transport; (b) active control of microturbulence and transport; (c) major disruptions; and (d) the sawtooth crash.

Date: January 1, 1992

Creator: Griem, H. R. & Liu, C. S.

Item Type: Report

Partner: UNT Libraries Government Documents Department