Search Results

Advanced search parameters have been applied.
open access

Stark broadening of isolated lines from high-Z emitters in dense plasmas

Description: The joint distribution of the electric microfield and its longitudinal derivative is required for the calculation of line profiles for the He-like ions in very dense plasmas. We used a molecular dynamics code to compute exact distributions in single- and multi-component plasmas, and then we investigated various analytical approximations to these results. We found that a simplified, two-nearest-neighbor scheme leads to surprisingly accurate distribution functions. Our results are illustrated by … more
Date: September 1, 1980
Creator: Weisheit, J.C. & Pollock, E.L.
Partner: UNT Libraries Government Documents Department
open access

Methods of driving current by heating a toroidal plasma

Description: In addition to the usual mechanism which utilizes the Ohmic transformer current, which is necessarily pulsed, there exist several steady-state mechanisms. Heating mechanisms which can lend themselves efficiently to continuous current generation include neutral beams, Alfven waves, ion-cyclotron waves, lower-hybrid waves and electron-cyclotron waves.
Date: August 1, 1980
Creator: Fisch, N. J.
Partner: UNT Libraries Government Documents Department
open access

Stack and area tritium monitoring systems for the tokamak fusion test reactor (TFTR)

Description: TFTR Tritium Stack and Area Monitoring Systems have been developed to provide the required level of reliability in a cost effective manner consistent with the mission of the Tritium Handling System on TFTR. Personnel protection, environmental responsibility, and tritium containing system integrity have been the considerations in system design. During the Deuterium-Tritium (D-T) experiments on TFTR, tritium will be used for the first time as one of the fuels. All of the tritium bearing systems w… more
Date: January 1, 1991
Creator: Pearson, G.G.; Meixler, L.D. & Sissingh, R.A.P.
Partner: UNT Libraries Government Documents Department
open access

ICRF heating on TFTR

Description: The objectives of the ICRF heating program on TFTR are discussed along with a summary of the progress made to date towards achieving those goals. A more detailed analysis of experimental observations of ICRF sawtooth stabilization is given along with a comparison of the data to a theoretical model based on energetic ion stabilization of m=1 kink instabilities. A qualitative correlation is observed between the experimental observations and model predictions, but further development of the theory… more
Date: January 1, 1991
Creator: Phillips, C. K.; Fredrickson, E.; Hammett, G.; Hosea, J.; McGuire, K.; Stevens, J. et al.
Partner: UNT Libraries Government Documents Department
open access

Methods for measuring the surface tritium inside TFTR using beta decay

Description: Three potential methods for measuring the surface tritium content of the TFTR vacuum vessel are described, each based on a different technique for measuring the in situ beta emission from tritium. These methods should be able to provide both a local and a global assessment of the tritium content within the top [approx] 1[mu]m of the inner wall surface.
Date: January 1, 1994
Creator: Zweben, S. J.; Johnson, D. & Hill, K. (Princeton Univ., NJ (United States). Plasma Physics Lab.) (and others)
Partner: UNT Libraries Government Documents Department
open access

ICRF (Ion Cyclotron Range of Frequencies) edge modeling studies

Description: Theoretical models have been developed, and are currently being refined, to explain the edge plasma-antenna interaction that occurs during ICRF heating. The periodic structure of a Faraday shielded antenna is found to result in strong ponderomotive force in the vicinity of the antenna. A fluid model, which incorporates the ponderomotive force, shows an increase in transport to the Faraday shield. A kinetic model shows that the strong antenna near fields act to increase the energy of deuterons w… more
Date: January 1, 1989
Creator: Lehrman, I.S. (Grumman Aerospace Corp., Princeton, NJ (USA). Corporate Research Center) & Colestock, P.L. (Princeton Univ., NJ (USA). Plasma Physics Lab.)
Partner: UNT Libraries Government Documents Department
open access

In-situ impurity measurements in PDX Edge plasma

Description: The surface analysis station of PDX combines several surface analysis techniques (AES, XPS, SIMS) for in-situ measurement of impurity fluxes in the edge-plasma. The major impurities deposited on a sample surface during nondiverted PDX discharges are oxygen, titanium (limiter material) and chlorine. The impurity fluxes measured at different radial positions decreased by a factor of ten from the plasma edge to the wall. The sample surface collecting the impurity ions is located behind a circular … more
Date: July 1, 1980
Creator: Staib, P.; Dylla, H.F. & Rossnagel, S.M.
Partner: UNT Libraries Government Documents Department
open access

Flow shear suppression of turbulence using externally driven ion Bernstein and Alfven waves

Description: The utilization of externally-launched radio-frequency waves as a means of active confinement control through the generation of sheared poloidal flows is explored. For low-frequency waves, kinetic Alfven waves are proposed, and are shown to drive sheared E {times} B flows as a result of the radial variation in the electromagnetic Reynolds stress. In the high frequency regime, ion Bernstein waves are considered, and shown to generate sheared poloidal rotation through the ponderomotive force. In … more
Date: January 1, 1991
Creator: Biglari, H.; Ono, M. (Princeton Univ., NJ (United States). Plasma Physics Lab.); Diamond, P.H. (California Univ., San Diego, La Jolla, CA (United States). Dept. of Physics) & Craddock, G.G. (Science Applications International Corp., San Diego, CA (United States))
Partner: UNT Libraries Government Documents Department
open access

Engineering design problems of TFTR

Description: Design of the TFTR poses special engineering problems as a result of constraints posed by the physics requirements of the fusion experiments. The ratio of plasma major and minor radii and the associated magnetic field strength required to achieve desired plasma conditions, the required confinement time, the two-component plasma concept, the complications of providing shielding from the 14 MeV neutrons and the necessity to control the inventory of tritium fuel, all constitute problems which, oft… more
Date: January 1, 1977
Creator: Lee, D.
Partner: UNT Libraries Government Documents Department
open access

Operation of the repeating pneumatic injector on TFTR and design of an 8-shot deuterium pellet injector

Description: The repeating pneumatic hydrogen pellet injector, which was developed at the Oak Ridge National Laboratory (ORNL), has been installed and operated on the Tokamak Fusion Test Reactor (TFTR). The injector combines high-speed extruder and pneumatic acceleration technologies to propel frozen hydrogen isotope pellets repetitively at high speeds. The pellets are transported to the plasma in an injection line that also serves to minimize the gas loading on the torus; the injection line incorporates a … more
Date: January 1, 1985
Creator: Combs, S. K.; Milora, S. L.; Foust, C. R.; Baylor, L. R.; Burris, R. D.; Fisher, P. W. et al.
Partner: UNT Libraries Government Documents Department
open access

Production of high density plasma by pellet injection in TFTR

Description: High plasma densities have been produced in ohmic and neutral beam heated discharges on TFTR using a repeating pneumatic pellet injector developed at Oak Ridge National Laboratory (ORNL). Line average plasma densities as high as 1 x 10/sup 14/ cm/sup -3/ have been attained by injection of five 2.7 mm deuterium pellets ..delta..n/sub e/ = 2 x 10/sup 14/ cm/sup -3/ over a one-second interval into a stetched neutral beam pulse. Injection of a single large (4 mm) pellet in ohmic discharge has produ… more
Date: January 1, 1985
Creator: Milora, S. L.; Schmidt, G. L.; Combs, S. K.; Bush, C. E.; Goldston, R. J.; Grek, B. et al.
Partner: UNT Libraries Government Documents Department
open access

Particle balance in a TFTR supershot

Description: Particle balance in a TFTR supershot is studied self-consistently. The TRANSP analysis code is used to model plasma parameters within the last closed flux surface, deriving time-dependent plasma profiles from measurements. The poloidal flux surfaces are derived using TRANSP and an equivalent-filament analysis code which distributes axisymmetric currents to match measurements of the poloidal field and flux and the total plasma current. The plasma in the edge and scrape off regions are modeled du… more
Date: January 1, 1992
Creator: Budny, R.V.; Coster, D.; Stotler, D.; Bell, M.G.; Janos, A.C. & Owens, D.K.
Partner: UNT Libraries Government Documents Department
open access

Comparison of methods for the production of neutral beams

Description: The fusion reactor neutral beam program consists principally of development and application of positive ion based systems in the energy range of less than or equal to 120 keV. Reactor studies for both mirrors and tokamaks, and even studies of tokamak research devices beyond TFTR, indicate a need for higher energies and also higher efficiencies than can be obtained by extrapolating positive ion based systems. The relative merits of systems based on positive ions, positive ions with energy recove… more
Date: December 1, 1977
Creator: Stewart, L. D.
Partner: UNT Libraries Government Documents Department
open access

Probe measurements of impurities in the plasma boundary of PLT

Description: Carbon probes were exposed to the plasma edge in PLT at various distances from the plasma and to different numbers (1, 2, 3, 6, 12) of overlayed discharges. The type and areal density of impurities retained were determined using ion backscattering. The principal impurities with Z > 6 were found to be O, Fe, Cr, Ti, and Cu in decreasing order of abundance. Fluxes for these impurities at a position close to the wall were found to be respectively 14, 2.8, 0.8, 0.6 and 0.2 x 10/sup 15//cm/sup 2/ (+… more
Date: January 1, 1980
Creator: Wampler, W.R.; Picraux, S.T.; Cohen, S.A.; Dylla, H.F.; Rossnagel, S.M. & McCracken, G.M.
Partner: UNT Libraries Government Documents Department
open access

Analytic representation of three-dimensional stellarator field

Description: The stellarator configuration can be greatly simplified when toroidal harmonics are introduced. The toroidal function satisfies Laplace's equation and together with toroidal field and vertical field, a small-aspect-ratio stellarator can be constructed with an aspect ratio as low as 3.6. This functional presentation suggests a very fast computation of particle orbits and magnetic configuration.
Date: September 1, 1983
Creator: Yoshikawa, S.
Partner: UNT Libraries Government Documents Department
open access

Computer simulations of anomalous transport

Description: Numerical plasma simulations have been carried out to study: (1) the turbulent spectrum and anomalous plasma transport associated with a steady state electrostatic drift turbulence; and (2) the anomalous energy transport of electrons due to shear-Alfven waves in a finite-..beta.. plasma. For the simulation of the steady state drift turbulence, it is observed that, in the absence of magnetic shear, the turbulence is quenched to a low level when the rotational transform is a rational number, whil… more
Date: July 1, 1980
Creator: Lee, W. W. & Okuda, H.
Partner: UNT Libraries Government Documents Department
open access

The effect of limiter conditioning on the Tokamak Fusion Test Reactor edge plasma

Description: Measurements by moveable Langmuir probes and edge spectroscopy diagnostics have documented the conditioning effect of low density helium-initiated discharge sequences on the Tokamak Fusion Test Reactor (TFTR) edge plasma. Langmuir probe measurements show in general that the edge electron density n{sub e} decreases by less than a factor of 2 while the edge electron temperature T{sub e} doubles. Radial profiles to the plasma boundary show that the density scrape-off length increases somewhat whil… more
Date: July 1, 1991
Creator: Kilpatrick, S. J.; Manos, D. M.; Nyberg, I.; Ramsey, A. T.; Stratton, B. C.; Timberlake, J. et al.
Partner: UNT Libraries Government Documents Department
open access

Confinement studies in TFTR

Description: The paper describes the present (end of February 1985) status of the plasma confinement studies in the TFTR tokamak with emphasis on those with neutral beam injection (NBI). Recent improvements in the device capabilities have substantially extended operating parameters: B/sub T/ increased to 4.0 T, I/sub p/ to 2.0 MA, injection power (P/sub b/) to 5 MW with H/sup 0/ or D/sup 0/ beams anti n/sub e/ to 5 x 10/sup 19/ m/sup -3/, and Z/sub eff/ reduced to 1.4. With ohmic heating (OH) alone, the pre… more
Date: June 1, 1985
Creator: Murakami, M.; Arunasalam, V.; Bell, J. D.; Bell, M. G.; Bitter, M.; Blanchard, W. R. et al.
Partner: UNT Libraries Government Documents Department
open access

Development of the TFTR Neutral Beam Injection System

Description: The TFTR Neutral Beam Lines are designed to inject 20 MW of 120 keV neutral deuterium atoms into the plasma. This is accomplished using 12 sources, 65 amperes each, mounted in 4 beam lines. The 120 kV sources and a prototype beam line are being developed. The implementation of these beam lines has required the development of several associated pieces of hardware. 200 kV switch tubes for the power supplies are being developed for modulation and regulation of the accelerating supplies. A 90 cm me… more
Date: January 1, 1977
Creator: Prichard, B. A., (Jr.)
Partner: UNT Libraries Government Documents Department
open access

TFTR DT preparation project status

Description: The objective of the DT Preparation Project on the Tokamak Fusion Test Reactor (TFTR) is to provide the capability required to perform a sequence of deuterium-tritium experiments in a manner which is consistent with DOE orders and the Environmental, Safety and Health requirements of DOE and PPPL. These experiments will include the study of confinement and heating of DT plasmas, determining the effects of alpha particles, demonstration of DT technical capability and the demonstration of DT power… more
Date: January 1, 1991
Creator: Perry, E. D. & Dudek, L. E.
Partner: UNT Libraries Government Documents Department
open access

TFTR remote maintenance

Description: The Tokamak Fusion Test Reactor (TFTR) is the first tokamak designed to utilize tritium plasmas and achieve significant neutron yields. Tritium operations are scheduled for the early 1980's at the Princeton Plasma Physics Laboratory. Complex operations of unprecedented scale must be performed remotely. The design of TFTR and the maintenance system supporting it are developing in parallel. The nature of the problem and a proposed set of maintenance tools are described.
Date: January 1, 1977
Creator: Bonanos, P. & Lontai, L.
Partner: UNT Libraries Government Documents Department
open access

Diagnostic interface problems on TFTR

Description: Diagnostic equipment on TFTR has functional interfaces with many machine systems. Salient requirements include plasma access, environmental resistance to thermal, magnetic and radiation effects, automated data acquisition and controls, remote handling and personnel safety. Problems imposed by these requirements and the solutions being considered are described.
Date: January 1, 1977
Creator: Goldfarb, S.
Partner: UNT Libraries Government Documents Department
open access

Measurements of the hydrogenic recombination coefficient for the TFTR vacuum vessel

Description: Characteristic values of the recombination rate coefficient for hydrogen and deuterium in stainless steel have been measured for the inner wall of the TFTR vacuum vessel for vessel temperatures of 25 to 100 C. In situ measurements of k/sub r/ are important for predicting the hydrogen isotope retention in the wall as a function of time, temperature, and discharge exposure, particularly because existing laboratory measurements of k/sub r/ for stainless steel span a range of four orders of magnitu… more
Date: December 1, 1983
Creator: Dylla, H. F.; Cecchi, J. L. & Knize, R. J.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen