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Laser intracavity absorption as a plasma diagnostic aid

Description: Trace levels of lithium are detected on 100 ..mu..sec timescales using an electrooptically tuned cw dye laser, in conjunction with a high resolution 0.03 A spectrometer/optical multichannel analyzer. The spectra of Li/sup 7/ resonance lines at 6708 A are analyzed for their Zeeman splitting patterns, after unfolding the effects of intracavity absorption (ICA) on the lineshape. For these timescales, a sensitivity to approx.1 x 10/sup 7/ lithium atoms/cc at a level of ..delta..I/I approx.10% has b… more
Date: January 1, 1985
Creator: Wurden, G. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A rad-hard, steady state, digital imaging bolometer system for ITER

Description: The concept and design of a new type of bolometer system which can function with excellent spatial resolution and good time resolution in the next generation of long-pulse (or steady-state), harsh-neutron environment fusion plasmas, is outlined. It uses a cooled pinhole camera design, employing a robust, passive, segmented radiation absorber, cooled from the back-side. Infrared emission from the absorber`s front surface is relayed by metal mirror optics to a shielded, high-resolution IR video c… more
Date: September 1, 1995
Creator: Wurden, G. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Harmonic launching of ion Bernstein waves via mode transformation

Description: Ion Bernstein wave excitation and propagation via finite ion-Larmor-radium mode-transformation are investigated theoretically and experimentally. It is shown that in the ion cyclotron range of frequencies omega less than or equal to 4..cap omega../sub i/, with modest ion temperatures (T/sub i/ less than or equal to 10 eV), the finite-Larmor-radius effect removes the wave singularity at lower-hybrid resonance layer, enabling an externally initiated electron plasma wave to transform continuously … more
Date: June 1, 1982
Creator: Ono, M.; Wong, K. L. & Wurden, G. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Ion Bernstein-wave excitation via finite-Larmor-radius mode-transformation process

Description: It is shown that in the ion cyclotron range of frequency ..omega.. less than or equal to 2 ..cap omega../sub i/, the finite-Larmor-radius effect removes the wave singularity at the lower-hybrid resonance layer, enabling an externally initiated electron plasma wave to propagate freely through the resonance layer, transforming continuously into an ion Bernstein wave. In an ACT-1 hydrogen plasma (T/sub e/ approx. = 2.5 eV, T/sub i/ approx. = 1.5 eV), linear excitation of ion Bernstein waves has be… more
Date: July 1, 1981
Creator: Ono, M.; Wong, K. L. & Wurden, G. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Ion temperature via laser scattering on ion Bernstein waves

Description: Hydrogen ion temperature has been measured in a warm toroidal plasma with externally launched ion Bernstein waves detected by heterodyne CO/sub 2/ laser scattering. Radial scanning of the laser beam allows precise determination of k/sub perpendicular to/ for the finite ion Larmor radius wave (..omega.. approx. less than or equal to 2..cap omega../sub i/). Knowledge of the magnetic field strength and ion concentration then give a radially resolved ion temperature from the dispersion relation. Pr… more
Date: October 1, 1981
Creator: Wurden, G. A.; Ono, M. & Wong, K. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Efficient ion heating via finite-Larmor-radius ICRF

Description: Ion heating by externally launched ion Bernstein waves is investigated in the ACT-1 hydrogen plasma. Detailed measurements of wave absorption and of the ion temperature profiles have clearly identified various heating layers near the ion cyclotron harmonics of deuterium-like and tritium-like ions. The observed heating of 10 eV/WATT/10/sup 10/ cm/sup -3/ and the power-balance estimates suggest excellent overall efficiency for FLR-ICRF heating.
Date: March 1, 1983
Creator: Ono, M.; Wurden, G. A. & Wong, K. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Lower hybrid wave resonance cone detection via CO/sub 2/ laser scattering

Description: Lower hybrid waves are studied in the Princeton ACT-I steady-state toroidal plasma device using a radially scanning CO/sub 2/ laser scattering system with both amplitude and phase sensitive detection techniques. Clearly defined resonance cones launched from external electrostatic antennas are seen to disappear as the plasma density is raised. Scaling of LHW laser signal with RF power in the presence of resonance cones shows nonlinearities associated with RF induced changes in the effective lase… more
Date: April 1, 1984
Creator: Wurden, G. A.; Wong, K. L. & Ono, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Tokamak physics experiment: Diagnostic windows study

Description: We detail the study of diagnostic windows and window thermal stress remediation in the long-pulse, high-power Tokamak Physics Experiment (TPX) operation. The operating environment of the TPX diagnostic windows is reviewed, thermal loads on the windows estimated, and cooling requirements for the windows considered. Applicable window-cooling technology from other fields is reviewed and its application to the TPX windows considered. Methods for TPX window thermal conditioning are recommended, with… more
Date: November 1, 1995
Creator: Merrigan, M. & Wurden, G. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Observation of magnetized-ion thermal effects on lower-hybrid waves

Description: Finite ion Larmor radius modification of lower-hybrid waves in the ACT-1 toroidal plasma at frequencies ..omega.. approx. = 4 to 8 ..omega../sub ci/, close to the lower-hybrid resonance layer, is observed experimentally. Probe and CO/sub 2/ laser scans of the wave amplitude show interference patterns at frequencies above each ion cyclotron harmonic. Modeling with a hot-ion, electrostatic ray tracing code and Fourier reconstruction of the waveform suggests that linear mode conversion to hot plas… more
Date: February 1, 1983
Creator: Wurden, G. A.; Wong, K. L.; Skiff, F. & Ono, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Operational Performance of the Two-Channel 10 Megawatt Feedback Amplifier System for MHD Control on the Columbia University HBT-EP Tokamak

Description: The operational characteristics and performance of the two channel 10 Megawatt MHD feedback control system as installed by Los Alamos National Laboratory on the Columbia University HBT-EP tokamak are described. In the present configuration, driving independent 300 {micro}H saddle coil sets, each channel can deliver 1100 Amperes and 16 kV peak to peak. Full power bandwidth is about 12 kHz, with capabilities at reduced power to 30 kHz. The present system topology is designed to suppress magnetohy… more
Date: October 6, 1997
Creator: Reass, W. A. & Wurden, G. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Experiences with remote collaborations in fusion research

Description: The magnetic fusion research community has considerable experience in placing remote collaboration tools in the hands of real user. The ability to remotely view operations and to control selected instrumentation and analysis tasks has been demonstrated. University of Wisconsin scientists making turbulence measurements on TFTR: (1) were provided with a remote control room from which they could operate their diagnostic, while keeping in close contact with their colleagues in Princeton. LLNL has a… more
Date: March 1998
Creator: Wurden, G. A.; Davis, S. & Barnes, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Conceptual design for a scintillating-fiber neutron detector for fusion reactor plasma diagnostics

Description: A conceptual design for a ``pointing`` neutron detector that is capable of delivering 10{sup 4} - 10{sup 5} Hz countrate of T(D,n) events from triton burnup at a deuterium-burning tokamak is described. The detector consists of collimated bundles of scintillating fibers that are separated by metal or polyethylene. These bundles in turn are set into a larger collimator that has some of the bundles set in ``unplugged`` holes and others in ``plugged`` holes whose countrate difference gives the net … more
Date: July 1, 1994
Creator: Sailor, W. C.; Barnes, C. W.; Chrien, R. E. & Wurden, G. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Initial Design of the 60 Megawatt Rotating Magnetic Field (RMF) Oscillator System for the University of Washington ''TCS'' Field Reversed Configuration Experiment

Description: This paper presents the initial electrical and mechanical design of two phase-locked 30 Megawatt RMS, 150 kHz oscillator systems used for current drive and plasma sustainment of the ''Translation, Confinement, and Sustainment'' (TCS) field reversed configuration (FRC) plasma. By the application of orthogonally-placed saddle coils on the surface of the glass vacuum vessel, the phase-controlled rotating magnetic field perturbation will induce an electric field in the plasma which should counter t… more
Date: October 6, 1997
Creator: Reass, W. A.; Miera, D. A. & Wurden, G. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Refueling and density control in the ZT-40M reversed field pinch

Description: The effects of pellet injection and gas puff refueling have been studied in the ZT-40M Reversed Field Pinch. Multiple deuterium pellets (less than or equal to 6 x 10/sup 19/D atoms/pellet) with velocities ranging from 300 to 700 m/sec have been injected into plasmas with n-bar/sub e/ approx.1 to 5 X 10/sup 19/m/sup -3/, I/sub phi/ approx.100 to 250 kA, T/sub e/(0) approx.150 to 300 eV and discharge durations of less than or equal to 20 msec. Photographs and an array D/sub ..cap alpha../ detecto… more
Date: January 1, 1987
Creator: Wurden, G. A.; Weber, P. G.; Watt, R. G.; Munson, C. P.; Cayton, T. E. & Buechl, K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Pellet injection in the RFP (Reversed Field Pinch)

Description: Observation of pellets injected into the ZT-40M Reversed Field Pinch has allowed a new twist on the usual tokamak ablation physics modeling. The RFP provides a strong ohmic heating regime with relatively high electron drift parameter (xi/sub drift/ /approximately/ 0.2), in the presence of a highly sheared magnetic field geometry. In situ photos of the pellet ablation cloud using a grated-intensified CCD camera, as well as two-view integrated photos of the pellet trajectory show substantial modi… more
Date: 1988~
Creator: Wurden, G. A.; Weber, P. G.; Munson, C. P.; Cayton, T. E.; Bunting, C. A. & Carolan, P. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Atlas chamber, power flow channel, and diagnostic interface design

Description: The Atlas pulsed-power machine, presently being designed at Los Alamos, will deliver a pulse of {approximately} 45 MA, in 4--5 {micro}sec, with energies of up to 6 MJ (from a bank of 36 MJ maximum) to a load assembly, located in vacuum. Design considerations for the vacuum vessel, power flow channel from the vessel inward, are presented. In contrast to Sandia`s PBFA II-Z, where 20 MA currents and 2--2.5 MJ of energy are delivered to ({approximately} 15 mg) loads in {approximately} 100 nsec, the… more
Date: September 1, 1997
Creator: Wurden, G. A.; Davis, H. A.; Taylor, A.; Bowman, D.; Ballard, E.; Ney, S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Design, construction, and first operational results of a 5 megawatt feedback controlled amplifier system for disruption control on the Columbia University HBT-EP tokamak

Description: This paper presents the electrical design and first operational results of a 5 Megawatt feedback controlled amplifier system designed to drive a 300 uH saddle coil set on the ``HBT-EP`` tokamak. It will be used to develop various plasma feedback techniques to control and inhibit the onset of plasma disruptions that are observed in high ``B`` plasmas. To provide a well characterized system, a high fidelity, high power closed loop amplifier system has been refurbished from the Los Alamos ``ZT-P``… more
Date: December 31, 1995
Creator: Reass, W. A.; Alvestad, H. A.; Bartsch, R. R.; Wurden, G. A.; Ivers, T. H. & Nadle, D. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Triton burnup study in JT-60U

Description: The behavior of 1 MeV tritons produced in the d(d,p)t reaction is important to predict the properties of D-T produced 3.5 MeV alphas because 1 MeV tritons and 3.5 MeV alphas have similar kinematic properties, such as Larmor radius and precession frequency. The confinement and slowing down of the fast tritons were investigated by measuring the 14 MeV and the 2.5 MeV neutron production rates. Here the time resolved triton burnup measurements have been performed using a new type 14 MeV neutron det… more
Date: October 1, 1995
Creator: Nishitani, T.; Hoek, M.; Isobe, M.; Tobita, K.; Kusama, Y.; Harano, H. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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THE ROTATING MAGNETIC FIELD OSCILLATOR SYSTEM FOR CURRENT DRIVE IN THE TRANSLATION, CONFINEMENT AND SUSTAINMENT EXPERIMENT

Description: The experimental setup and test results for the {approximately}125 MW rotating magnetic field current drive system of the Translation, Confinement and Sustainment Experiment at the University of Washington are described. The oscillator system, constructed at Los Alamos National Laboratory, drives two tank circuits (15 kV{sub peak} potential, 8.5 kA{sub peak} maximum circulating current in each tank to date) operated 90{degree} out of phase to produce a 54 G rotating magnetic field with a freque… more
Date: December 1, 2000
Creator: Tobin, S. J.; Reass, W. A.; Schrank, L. S.; Wurden, G. A.; Guo, H. Y.; Hoffman, A. L. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A scintillating-fiber 14-MeV neutron detector on TFTR during DT operation

Description: A compact 14-MeV neutron detector using an array of scintillating fibers has been tested on the TFTR tokamak under conditions of a high gamma background. This detector uses a fiber-matrix geometry, a magnetic field-insensitive phototube with an active HV base and pulse-height discrimination to reject low-level pulses from 2.5 MeV neutron and intense gammas. Laboratory calibrations have been performed at EG&G Las Vegas using a pulsed DT neutron generator and a 30 kCi {sup 60}Co source as backgro… more
Date: July 1, 1994
Creator: Wurden, G. A.; Chrien, R. E.; Barnes, C. W.; Sailor, W. C.; Roquemore, A. L.; Lavelle, M. J. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Active Control of 2/1 Magnetic Islands in the HBT-EP Tokamak

Description: Closed and open loop control techniques were applied to growing m/n=2/1 rotating islands in wall stabilized plasmas in the HBT-EP tokamak. The approach taken by HBT-EP combines an adjustable segmented conducting wall (which slows the growth or stabilizes ideal external kinks) with a number of small (6{degree} wide) saddle coils located between the gaps of the conducting wall. In this paper we report demonstration of 2-phase island rotation control from 5 kHz to 15 kHz and observation of the pha… more
Date: November 18, 1997
Creator: Navratil, G. A.; Cates, C.; Mauel, M. E.; Maurer, D.; Nadle, D.; Taylor, E. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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