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in subjects: "Ion Temperature"

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Hot-ion distribution function in ORMAK, the Oak Ridge Tokamak

A distortion of the Maxwellian ion-energy distribution function in tokamak-produced plasmas may be revealed in the spectral-line radiation. We report experimental evidence that (1) a change in the value of Z/sub eff/, (2) delayed gas injection, (3) neutral beam injection, and (4) liner cleaning procedures can alter the profile of the Balmer-..cap alpha.. (6563 A) line of hydrogen. The distortion is analyzed in terms of an effective toroidal-drift velocity, ion-temperature relation.

Date: March 1, 1978

Creator: Neidigh, R.V. & Sigmar, D.J.

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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Analytical theory of ion-temperature-gradient instability

The relationship between the threshold values of ion-temperature-gradient instabilities and the temperature parameters of plasmas is investigated analytically in slab and toroidal geometries separately. It is found that the threshold values increase rapidly when the ion temperature becomes much higher than the electron temperature. The change of the threshold vaues with respect to the ion temperature is quite similar for both geometric models. This finding is consistent with PLT observations. F… more

Date: January 19, 1982

Creator: Guo, S.; Shen, J.; Chen, L. & Tsai, S.T.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Tokamak and RFP ignition requirements

A plasma model is applied to calculate numerically transport- confinement (n{tau}{sub E}) requirements and steady-state operation tokamak. The CIT tokamak and RFP ignition conditions are examined. Physics differences between RFP and tokamaks, and their consequences for a DT ignition machine, are discussed. The ignition RFP, compared to a tokamak, has many physics advantages, including ohmic heating to ignition (no need for auxiliary heating systems), higher beta, low ignition current, less sens… more

Date: January 1, 1991

Creator: Werley, K.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Convective equilibrium and mixing-length theory for stellarator reactors

In high ..beta.. stellarator and tokamak reactors, the plasma pressure gradient in some regions of the plasma may exceed the critical pressure gradient set by ballooning instabilities. In these regions, convective cells break out to enhance the transport. As a result, the pressure gradient can rise only slightly above the critical gradient and the plasma is in another state of equilibrium - ''convective equilibrium'' - in these regions. Although the convective transport cannot be calculated pre… more

Date: September 1, 1985

Creator: Ho, D.D.M. & Kulsrud, R.M.

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

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The ARIES-III D- sup 3 He tokamak reactor: Design-point determination and parametric studies

The multi-institutional ARIES study has generated a conceptual design of another tokamak fusion reactor in a series that varies the assumed advances in technology and physics. The ARIES-3 design uses a D-{sup 3}He fuel cycle and requires advances in technology and physics for economical attractiveness. The optimal design was characterized through systems analyses for eventual conceptual engineering design. Results from the systems analysis are summarized, and a comparison with the high-field, D… more

Date: January 1, 1991

Creator: Bathke, C. G.; Werley, K. A.; Miller, R. L.; Krakowski, R. A. (Los Alamos National Lab., NM (United States)) & Santarius, J. F. (Wisconsin Univ., Madison, WI (United States))

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Vortices associated with toroidal ion temperature gradient driven fluctuations

The three nonlinear hydrodynamic equations for potential, parallel ion velocity and ion pressure used in simulations of the toroidal ion temperature gradient driven fluctuations and transport in a shear magnetic field are analyzed for coherent vortex structures. Two types of vortex structures are found: one type for weak shear that is a generalization of the usual modon vortex construction and the second type of solution for strong magnetic shear where the convective nonlinearity in the paralle… more

Date: May 1, 1992

Creator: Horton, W. (Texas Univ., Austin, TX (United States). Inst. for Fusion Studies); Jovanovic, D. (Belgrade Univ. (Yugoslavia). Inst. za Fiziku) & Rasmussen, J.J. (Association Euratom-Risoe National Lab., Roskilde (Denmark))

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Ion-temperature-gradient instability in toroidal plasmas

The stability of the ion-temperature-gradient mode in a toroidal plasma is investigated. Using the ballooning-mode formalism, an ordinary difference-differential equation is derived which includes full kinetic effects. The equation is, then, examined in various limits where it reduces to an ordinary differential equation. Analytic and computational studies show that, for eta/sub i/ identical with d lnT/sub i//d lnn > 1, toroidal effects further destabilize the mode and, hence, the corresponding… more

Date: March 1, 1980

Creator: Guzdar, P.N.; Chen, L.; Tang, W.M. & Rutherford, P.H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Measurement of the central ion and electron temperature of tokamak plasmas from the x-ray line radiation of high-Z impurity ions

This paper describes measurements of the central ion and electron temperature of tokamak plasmas from the observation of the 1s - 2p resonance lines, and the associated dielectronic (1s/sup 2/nl - 1s2pnl, with n greater than or equal to 2) satellites, of helium-like iron (Fe XXV) and titanium (Ti XXI). The satellite to resonance line ratios are very sensitive to the electron temperature and are used as an electron temperature diagnostic. The ion temperature is deduced from the Doppler width of … more

Date: April 1, 1982

Creator: Bitter, M.; Von Goeler, S.; Goldman, M.; Hill, K.W.; Horton, R.; Roney, W. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Advanced-fueled fusion reactors suitable for direct energy conversion. Fourth quarterly progress report: October 1976--December 1976 and first quarterly progress report: January 1977--March 1977

The direct energy conversion efficiencies calculated for Cat-D and D-/sup 3/He fueled Tokamak reactors are summarized over a range of reactor designs, collector configurations, assumed T/sub e//T/sub i/ ratios, and power densities. The performance of a system of superconducting coils that produce those fields required to guide escaping plasma along the path between the bundle divertor coils and the direct converter is also discussed.

Date: September 9, 1977

Creator: Blum, A. S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Quasi-steady operation of reversed field pinches

A three fluid, Lagrangian mesh, transport and stability code (RFPBRN) has been developed and applied to the Reversed Field Pinch reactor concept. Using a circular cylinder, quasi-static approximation, RFPBRN follows the time evolution of the temperature, density, and magnetic field profiles for the RFP while simultaneously monitoring ideal MHD stability. Local stability is monitored for Suydam modes while global stability is monitored using a Rayleigh-Ritz expansion of the energy principle.

Date: January 1, 1980

Creator: Nebel, R.A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Characteristics of ion Bernstein wave heating in JIPPT-II-U tokamak

Using a transport code combined with an ion Bernstein wave tokamak ray tracing code, a modelling code for the ion Bernstein wave heating has been developed. Using this code, the ion Bernstein wave heating experiment on the JIPPT-II-U tokamak has been analyzed. It is assumed that the resonance layer is formed by the third harmonic of deuterium-like ions, such as fully ionized carbon, and oxygen ions near the plasma center. For wave absorption mechanisms, electron Landau damping, ion cyclotron ha… more

Date: November 1, 1985

Creator: Okamoto, M. & Ono, M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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High beta capture and mirror confinement of laser produced plasmas. Final report

The LITE fusion plasma research program at UTRC has been investigating the stabilization and confinement physics of a mirror plasma created by energetic neutral beam heating of a confined target plasma. During the period covered by this report work has been concentrated on the investigation of hot ion losses in a warm target plasma, development of a cryocondensation pump for the LITE beam line neutralizer, theoretical studies of ECRH modification of the ambipolar potential in mirror plasmas, an… more

Date: December 1, 1977

Creator: Haught, A.F.; Tomlinson, R.G.; Ard, W.B.; Boedeker, L.R.; Churchill, T.L.; Fader, W.J. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Self-consistent calculations of edge temperature and self-sputtering of the limiter surface for tokamak fusion reactors

Self-sputtering and edge temperature estimates have been made for a tokamak fusion reactor with a normal incidence boundary using models for the power balance, plasma sheath, charge state, and sputtering coefficients. Both structural materials and low-Z coatings have been examined. From the self-sputtering standpoint, some materials will work only at very low edge temperatures; these will require a high recycling rate and a high radiation fraction.

Date: May 1, 1980

Creator: Brooks, J. N.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Status of the USA program on the development of submillimeter lasers to measure ion temperatures

The concept of ion laser scattering is outlined briefly and the parameters of the required submillimeter laser system are described. The current state of the development of lasers, laser and viewing dumps, and detectors is reviewed. (MHR)

Date: January 1, 1977

Creator: Barnett, C. F.; Hutchinson, D. P.; Vander Sluis, K. & Staats, P. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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(Ion temperature gradient instability and transport: Progress report)

Anomalous ion thermal conductivity remains in open physics issue for the present generation of high temperature Tokamaks. It is now believed to be due to the Ion Temperature Gradient (ITG or n{sub i}) instability. The production and identification of this instability is being studied in the simpler and experimentally convenient configuration of the steady state Columbia Linear Machine (CLM). The slab branch of this instability has been produced (by two different heating methods), identified and… more

Date: January 1, 1992

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Observation of lines above 2000 A in OVIII and CVI in the PLT tokamak due to charge-exchange processes: diagnostic applications

Hydrogen-like oxygen and carbon lines from high-n transitions with wavelengths above 2000 A were observed as a result of charge-exchange processes during neutral beam injection of hydrogen atoms into the Princeton Large Torus (PLT) tokamak. The lines are: OVIII 2976 A (8 ..-->.. 7 transitions), CVI 3434 A (7 ..-->.. 6), and CVI 5291 A (8 ..-->.. 7). Application of these lines for Doppler ion temperature measurements and initial obeservations of neutral beam vertical and horizontal distributions… more

Date: February 1984

Creator: Suckewer, S.; Skinner, C. H.; Stratton, B.; Bell, R.; Cavallo, A.; Hosea, J. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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MTX (Microwave Tokamak Experiment) diagnostic and auxiliary systems for confinement, transport, and plasma physics studies

This note describes the diagnostics and auxiliary systems on the Microwave Tokamak Experiment (MTX) for confinement, transport, and other plasma physics studies. It is intended as a reference on the installed and planned hardware on the machine for those who need more familiarity with this equipment. Combined with the tokamak itself, these systems define the opportunities and capabilities for experiments in the MTX facility. We also illustrate how these instruments and equipment are to be used … more

Date: July 28, 1989

Creator: Hooper, E. B.; Allen, S. L.; Casper, T. A. & Thomassen, K. I.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Lower-hybrid-heating experiments on the Alcator C and the Versator II tokamaks

Initial results are reported from lower hybrid wave heating experiments carried out on the MIT Alcator C and Versator II tokamaks. In the Alcator C experiments a 4 waveguide array, with internally brazed ceramic windows has been used to inject 160 kW of microwave power at 4.6 GHz into the plasma with n/sub 0/ less than or equal to 1 x 10/sup 15/ cm/sup -3/, and B/sub 0/ less than or equal to 12 T. An RF power density of 8 kW/cm/sup 2/ has been transmitted into the plasma without RF breakdown. R… more

Date: January 1, 1982

Creator: Takase, Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Fast-wave ICRF heating for EBT-P

Supplementary ion heating will play a major role in advancing the physics understanding of bumpy tori in EBT-P. Fast-wave ICRF heating is the method selected for EBT-P because of the successful ICRF heating experiments on tokamaks and on EBT-S. Given neoclassical electron behavior, then 2 MW of ICRF heating in the range of 60 to 90 MHz should be sufficient for the achievement of all the goals for ion heating, including 5% core plasma beta at the rings.

Date: January 1, 1982

Creator: Baity, F.W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Tandem Mirror Reactor Systems Code (Version I)

A computer code was developed to model a Tandem Mirror Reactor. Ths is the first Tandem Mirror Reactor model to couple, in detail, the highly linked physics, magnetics, and neutronic analysis into a single code. This report describes the code architecture, provides a summary description of the modules comprising the code, and includes an example execution of the Tandem Mirror Reactor Systems Code. Results from this code for two sensitivity studies are also included. These studies are: (1) to de… more

Date: September 1, 1985

Creator: Reid, R. L.; Finn, P. A.; Gohar, M. Y.; Barrett, R. J.; Gorker, G. E.; Spampinaton, P. T. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Measurement of the 2. 35 MeV window in O + n

Calculations are made showing that the ion temperature of a deuterium plasma with a Maxwellian distribution can be found by measuring the transmission of the d-d neutrons through liquid oxygen. The method is useful for temperatures up to 6 keV. It does not depend on the absolute neutron yield but does require accurate total neutron cross sections for oxygen. In this experiment the cross section of natural oxygen was measured from 2.0 to 3.0 by neutron time-of-flight at the Oak Ridge Electron Li… more

Date: January 1, 1979

Creator: Johnson, C. H.; Fowler, J. L.; Hill, N. W. & Ortolf, J. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department