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Direct electron heating by 60 MHz fast waves on DIII-D

Description: Efficient direct electron heating by fast waves has been observed on the DIII-D tokamak. A four strap antenna with (0,{pi},0,{pi}) phasing launched up to 1.6 MW of fast wave power with {vert bar}n{sub {parallel}}{vert bar} {approx} 11. This {vert bar}n{sub {parallel}}{vert bar} is suitable for strong electron interaction in ohmic target plasmas (T{sub e} {le} 2 keV). Ion cyclotron absorption was minimized by keeping the hydrogen fraction low ({lt}3%) in deuterium discharges and by operating at … more
Date: October 1, 1991
Creator: Petty, C. C.; Pinsker, R. I.; Mayberry, M. J.; Chiu, S. C.; Luce, T. C.; Prater, R. (General Atomics, San Diego, CA (United States)) et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Theory-based transport simulations of TFTR L-mode temperature profiles

Description: The temperature profiles from a selection of TFTR L-mode discharges are simulated with the 1-1/2-D BALDUR transport code using a combination of theoretically derived transport models, called the Multi-Mode Model. The present version of the Multi-Mode Model consists of effective thermal diffusivities resulting from trapped electron modes and ion temperature gradient ({eta}{sub i}) modes, which dominate in the core of the plasma, together with resistive ballooning modes, which dominate in the per… more
Date: October 24, 1991
Creator: Bateman, G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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ECE and x-ray image reconstructions of sawtooth oscillations on TFTR

Description: High resolution ECE and X-ray image reconstructions have been made simultaneously during the sawtooth crash in the fast rotating plasma on TFTR. The X-ray tomography is found not the represent flux surfaces but to show metal impurity behavior. The experimental results show that the reconnection process cause the sawtooth crash, even when the crash time is 20 times faster than the Kadomtsev reconnection time. New features are observed during the sawtooth crash, such as an oval shaped hot spot an… more
Date: October 1, 1991
Creator: Nagayama, Y.; McGuire, K.M.; Cavallo, A.; Bitter, M.; Fredrickson, E.D.; Hill, K.W. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Algorithm for the computation of nonlinear electron thermal conduction on an arbitrarily shaped, two-dimensional domain

Description: A numerical algorithm is described for computing coupled heat and hydrodynamic flow on an arbitrarily shaped, time-varying domain. The algorithm extends the ICED-ALE method, for the computation of hydrodynamic motion using an arbitrary Eulerian-Lagrangian mesh, to include electron thermal conduction. Appropriate difference equations in conservation form are developed, and the Dufort-Frankel scheme is adapted to advance these equations in time. Results are presented which illustrate the applicat… more
Date: October 1, 1977
Creator: Brackbill, J.U. & Margolin, L.G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Analysis of dense pusher laser-driven implosions for intermediate densities

Description: Post-shot analysis of targets designed to achieve a diagnosible compression of DT gas to 2. g/cm/sup 3/ or 10 x liquid density is reported. The SHIVA laser provided 15 to 20 TW of 1.06 ..mu..m laser light. Detailed comparisons of diagnostic results with hydro-code calculations are made. Implications for laser light absorption/scattering, thermal conduction, suprathermal electron preheat, implosion symmetry, and pusher-fuel mix are discussed. Uncertainties of the density determination methods ar… more
Date: October 24, 1979
Creator: Mead, W. C.; Orth, C. D.; Bailey, D. S.; McClellan, G. & Estabrook, K. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Software Engineering Processes Used to Develop the NIF Integrated Computer Control System

Description: We have developed a new target platform to study Laser Plasma Interaction in ignition-relevant condition at the Omega laser facility (LLE/Rochester)[1]. By shooting an interaction beam along the axis of a gas-filled hohlraum heated by up to 17 kJ of heater beam energy, we were able to create a millimeter-scale underdense uniform plasma at electron temperatures above 3 keV. Extensive Thomson scattering measurements allowed us to benchmark our hydrodynamic simulations performed with HYDRA [1]. As… more
Date: October 3, 2007
Creator: Ludwigsen, A P; Carey, R W; Demaret, R D; Lagin, L J; Reddi, U P & Van Arsdall, P J
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Green (2(omega)) Laser Beam propagation in high-temperature Hohlraum Plasmas

Description: We demonstrate propagation and small backscatter losses of a frequency-doubled (2{omega}) laser beam interacting with inertial confinement fusion hohlraum plasmas. The electron temperature of 3.3 keV, approximately a factor of two higher than achieved in previous experiments with open geometry targets, approaches plasma conditions of high-fusion yield hohlraums. In this new temperature regime, we measure 2{omega} laser beam transmission approaching 80% with simultaneous backscattering losses of… more
Date: October 26, 2007
Creator: Niemann, C; Berger, R; Divol, L; Froula, D H; Jones, O S; Kirkwood, R K et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Compton scattering measurements from dense plasmas

Description: Compton scattering has been developed for accurate measurements of densities and temperatures in dense plasmas. One future challenge is the application of this technique to characterize compressed matter on the National Ignition Facility where hydrogen and beryllium will approach extremely dense states of matter of up to 1000 g/cc. In this regime, the density, compressibility, and capsule fuel adiabat may be directly measured from the Compton scattered spectrum of a high-energy x-ray line sourc… more
Date: October 2, 2007
Creator: Glenzer, S. H.; Neumayer, P.; Doeppner, T.; Landen, L.; Lee, R. W.; Wallace, R. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Studies on Neutral Beam Injection into the SSPX Spheromak Plasma

Description: In the Sustained Spheromak Physics Experiment, (SSPX) ['Improved operation of the SSPX spheromak', R.D. Wood, D.N. Hill, E.B. Hooper, S. Woodruff1, H.S. McLean and B.W. Stallard, Nucl. Fusion 45 1582-1588 (2005)], plasmas with core electron temperatures reaching up to 500 eV at densities of 10{sup 20}/m{sup 3} have been sustained for several milliseconds, making them suitable as targets for neutral beam injection. High performance and further progress in understanding Spheromak plasma physics a… more
Date: October 19, 2007
Creator: Jayakumar, R; Pearlstein, L D; Casper, T A; Fowler, T K; Hill, D N; Hudson, B et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Global confinement in the MST (Madison Symmetric Torus) reversed field pinch

Description: Global confinement measured in the first six months of MST full design operation is summarized. Central electron temperature and enhancement of resistivity over the Z = 1 Spitzer value are similar to other RFP experiments for the same value of I/N. As in several other RFP experiments, energy confinement time and poloidal beta are found to decrease with increasing plasma current, with maximum values of {tau}{sub E} {approximately} 1 ms and {beta}{sub p} {approximately} 10%. Particle transport ma… more
Date: October 1, 1990
Creator: Almagri, A.; Assadi, S.; Beckstead, J.; Chartas, G.; Cudzinovic, M.; Den Hartog, D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Progress in toroidal confinement and fusion research

Description: During the past 30 years, the characteristic T/sub i/n tau/sub E/-value of toroidal-confinement experiments has advanced by more than seven orders of magnitude. Part of this advance has been due to an increase of gross machine parameters. Most of this advance has been due to an increase of gross machine parameters. Most of the advance is associated with improvements in the ''quality of plasma confinement.'' The combined evidence of spherator and tokamak research clarifies the role of magnetic-f… more
Date: October 1, 1987
Creator: Furth, H.P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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MFTF-B electron-cyclotron-resonance heating system

Description: The MFTF-B ECRH system will provide 1.6-MW of microwave power for heating of electrons within the thermal barrier and potential maximum regions of the plasma end-plugs. Absorption of this radiation increases the resonant electron energy which locally alters the electrostatic confining potential within the plasma. The result is a thermal barrier which will isolate end-plug electrons from those in the solenoid thus increasing the plasma confinement time. Microwave energy will be generated by eigh… more
Date: October 22, 1981
Creator: Krause, K. H.; Pollock, G. G. & Yugo, J. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Measurements of optically thin electron cyclotron emission from relativistic electrons

Description: Electron cyclotron emission (ECE) from hot, relativistic electrons has been measured simulataneously at several optically thin frequencies (f/f/sub ce/ = 4.6, 7.0, and 9.6) on the Tandem Mirror Experiment-Upgrade. A method to determine the temporal evolution of the hot electron density, n/sub h/, and temperature T/sub h/ is discussed. Calculations of T/sub h/ agree with the analysis of the high energy x-ray spectra. Heating rates vary between 3 keV/ms and 13 keV/ms and temperatures over 300 keV… more
Date: October 1, 1987
Creator: James, R. A.; Silver, E.; Boyd, D.; Ellis, R. F.; Jantz, S.; Lasnier, C. J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Experimental Test of Resonant Absorption Theory Progress Report: July-September 1979

Description: The scaling of the hot electron temperature, T/sub h/, with laser intensity, I, has been studied with the laser-shockfront interaction apparatus. The preliminary result for 500 psec laser pulses of intensity I approx. 10/sup 14/ W/cm/sup 2/ is T/sub h/ infinity I/sup ..cap alpha../, where ..cap alpha.. = .35 to .40.
Date: October 1, 1979
Creator: Yablonovitch, Eli
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Analysis of non-inductive current drive from ECCD and bootstrap on T-10

Description: The combination of electron cyclotron current drive and the bootstrap effect has produced completely non-inductively driven current of 75kA for up to 200 msec in the T-10 tokamak. At higher values of plasma current I{sub p} {approximately} 175kA, I{sub p} {ge} 60kA was maintained by ECCD. These experiments have been modeled with the coupled ray training and transport codes TORAY and ONETWO. Within the uncertainties in the experimental data, the calculations show that the sum of bootstrap and EC… more
Date: October 1, 1991
Creator: Lohr, J.; Harvey, R.W.; Luce, T.C.; Petty, C.C. (General Atomics, San Diego, CA (United States)); James, R.A. (Lawrence Livermore National Lab., CA (United States)); Alikaev, V.V. et al.
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Partner: UNT Libraries Government Documents Department
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FY90 milestone report for the CIT (Compact Ignition Tokamak) project: Localizability of electron-cyclotron heating power

Description: Estimates of the localizability of electron-cyclotron heating power are made for the Compact Ignition Tokamak. A particular heating scenario is examined, namely, the fundamental O-mode, injected nearly perpendicular to the toroidal magnetic field. The absorption depth due to finite T{sub e} is very small, about 1 cm, near the q = 2 surface. Absorption is even better localized near q = 1. Several issues that might lead to degraded localizability are reviewed. Use of an intense, pulsed microwave … more
Date: October 25, 1990
Creator: Smith, G. R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Transport and stability studies on TFTR

Description: During the 1987 run, TFTR reached record values of Q/sub DD/, neutron source strength, and T/sub i/(0). Good confinement together with intense auxiliary heating has resulted in a plasma pressure greater than 3 x 10/sub 5/ Pascals on axis, which is at the ballooning stability boundary. At the same time improved diagnostics, especially ion temperature profile measurements, have led to increased understanding of tokamak confinement physics. Ion temperature profiles are found to be much more peaked… more
Date: October 1, 1988
Creator: McGuire, K.M.; Arunasalam, V.; Barnes, C.W.; Bell, M.G.; Bitter, M.; Bosch, H.S. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Buildup studies of a tandem mirror reactor with inboard thermal barriers

Description: The build-up and quasi-steady state phases of the operation of the tandem mirror experiment, TMX, and of a tandem mirror machine with inboard thermal barriers, MFTF-B, have been simulated using a fluid model of the central cell and plug plasmas. The fluid model incorporates classical radial transport, three-dimensional cold gas transport in cylindrical geometry, and neutral beam transport corrected for finite-Larmor-orbit effects in both the central cell and yin yang end plugs.
Date: October 9, 1980
Creator: Gryczkowski, G. E. & Gilmore, J. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Temperature diagnostics using lithium-like satellites

Description: A 60-kJ theta-pinch was operated at a filling pressure of 16 mtorr using a gas mixture of 2% neon and 98% helium. The resonance and intercombination lines from Ne IX and the Li-like satellites were observed with a Bragg crystal monochromator. The electron temperature of the plasma was deduced from the intensity ratios of the Ne IX resonance line and the dielectronic satellites using recent theoretical calculations. The temperature values ranged from 210 eV to 340 eV during the time of occurrenc… more
Date: October 1, 1980
Creator: Datla, R. U.; Jones, L. A. & Thomson, D. B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Summary of mirror experiments relevant to beam-plasma neutron source

Description: A promising design for a deuterium-tritium (DT) neutron source is based on the injection of neutral beams into a dense, warm plasma column. Its purpose is to test materials for possible use in fusion reactors. A series of designs have evolved, from a 4-T version to an 8-T version. Intense fluxes of 5--10 MW/m/sup 2/ is achieved at the plasma surface, sufficient to complete end-of-life tests in one to two years. In this report, we review data from earlier mirror experiments that are relevant to … more
Date: October 18, 1988
Creator: Molvik, A.W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Local carbon diffusion coefficient measurement in the S-1 spheromak

Description: The local carbon diffusion coefficient was measured in the S - 1 spheromak by detecting the radial spread of injected carbon impurity. The radial impurity density profile is determined by the balance of ionization and diffusion. Using measured local electron temperature T/sub e/ and density n/sub e/, the ionization rate is determined from which the particle diffusion coefficient is inferred. The results found in this work are consistent with Bohm diffusion. The absolute magnitude of D/sub /perp… more
Date: October 1, 1988
Creator: Mayo, R.M.; Levinton, F.M.; Meyerhofer, D.D.; Chu, T.K.; Paul, S.F. & Yamada, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Measurements of the /sup 3/He fusion product in TFTR

Description: The 0.8-MeV /sup 3/He ion created in the d(d,n)/sup 3/He fusion reaction is confined in TFTR and can undergo d(/sup 3/He,p)..cap alpha.. fusion reactions. The time evolution, and profile of the 14.7-MeV proton emission indicates that collisional energy transfer with plasma electrons is the dominant process influencing the charged /sup 3/He fusion product for TFTR plasmas and that there is no observable anomalous transport. The magnitude of the burnup exceeds classical expectations by a factor-o… more
Date: October 1, 1988
Creator: Strachan, J.D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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