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Thursday, January 30, 2020 | History

3 edition of Alpha-driven, steady-state tokamak found in the catalog.

Alpha-driven, steady-state tokamak

J. Rand McNally

Alpha-driven, steady-state tokamak

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Published by Dept. of Energy, [Office of Energy Technology], Oak Ridge National Laboratory, for sale by the National Technical Information Service in Oak Ridge, Tenn, Springfield, Va .
Written in English

    Subjects:
  • Tokamaks

  • Edition Notes

    StatementJ. Rand McNally, Jr. ; prepared by the Oak Ridge National Laboratory
    SeriesORNL/TM ; 6492
    ContributionsOak Ridge National Laboratory
    The Physical Object
    Pagination19 p. :
    Number of Pages19
    ID Numbers
    Open LibraryOL14881638M

    Further restriction is obtained by choosing a set of plasma data which are sufficient to describe the most important features of the plasma neutron source. Then, the third version of the neutron transport code MCNP was released in which was the first version of this code that has been internationally distributed [16]. Even if hybrids are mainly limited by tearing modes, proximity to the no-wall limit leads to 3D field amplification that affects plasma profiles, e. This established the tokamak as the leading contender for a thermonuclear confinement system and, hence, over the past decades the international magnetic confinement fusion research programme has been mainly focusing on tokamak fusion devices. However, such comparisons require both, theoretical calculations for realistic configurations and conditions, as well as rather detailed and accurately measured plasma properties.

    The variety of neutron measurements that can be made on fusion experiments is limited to measuring the total emission strength, the relative spatial emissivity in the plasma, and the energy spectra of neutrons emitted from small plasma volumes or from selected lines-of-sight through the plasma. Therefore, the remainder of Section 2 is mainly concerned with the calculation of ion velocity distributions in the presence of neutral-beam heating by means of a Fokker—Planck formalism. General remarks 3. At higher densities, experiments and modeling with ray tracing and full-wave codes suggest that excessive wave interaction in outer regions of the plasma combined with low single-pass absorption are responsible for markedly lower efficiency. Since experimental results for 14 MeV neutrons from D—T operation are, as yet, only available from TFTR [20—26] and JET [27—31], this article is devoted to reviewing the numerical modelling and analysis techniques of 2. In particular, validation of the predictions for ITER in retention levels, breakdown at low voltage, H-mode threshold, confinement level and erosion rates are part of the on-going studies and results obtained so far demonstrate agreement with initial expectations.

    Furthermore, in practice, at many tokamak experiments neutron measurements are viewed primarily as fast-ion diagnostics and only secondarily as plasma diagnostics which to some extent obscures the view on the general progress. Therefore, an overview on the concepts and available computer codes for calculating neutral-beam deposition data are given. Studies of MHD activity and fast-ion confinement 5. In plasma experiments neutrons are being produced by nuclear reactions of the fuel ions. As illustrative examples, analytic results for Maxwellian deuterium plasmas have been included.


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Alpha-driven, steady-state tokamak book

This established the tokamak as the leading contender for a thermonuclear confinement system and, hence, over the past decades the international magnetic confinement fusion research programme has been mainly focusing on tokamak fusion devices.

It starts with a brief overview on fusion reactions and cross sections, the calculation of fusion reactivities, neutron spectra and the neutron transport equation. Mills Contents steady-state tokamak book. Theoretical background of the fusion neutron emission The emitted neutron rate Alpha-driven a plasma is a weighted average of the velocity distribution with cross section and relative velocity and the neutron spectrum is simply the energy-dependent probability of neutron emission per steradian.

A new management structure was introduced in and several new communication channels were established with the DAs. This bibliographic database contains more than references on fusion reaction cross sections, diagnostics and plasma physics studies B.

Secondly, computer codes for neutron transport calculations are needed in order to assess the influence of neutron scattering and absorption on the measured neutron signals. Accurately measured basic plasma data and neutron signals are needed as input data.

Derivation of ion densities 4. Two of ten sections of inboard side helical divertor were modified to a baffled structure as a pilot, and neutral compression of more than 10 times was demonstrated, which agrees with the prediction of 3-D Monte Carlo simulation. For thermal plasmas modelling the ion velocity distribution and inferring plasma data from the neutron signals is a straightforward procedure.

The properties of this signal depends on the properties of the incident neutrons as well as on the detector properties. This bibliographic review contains many of the citations with more experimental focus that are contained in the compilation by Bosch.

Furthermore, in practice, at many tokamak experiments neutron measurements are viewed primarily as fast-ion diagnostics and only secondarily as plasma diagnostics which to some extent obscures the view on the general progress. Using a retarding field analyser, fluctuating and average ion temperatures were measured in the far SOL which allows assessing the power flux on the first wall.

Pellet pacing experiments with injection geometry similar to that planned for ITER produced a ten-fold increase in the ELM frequency and a strong reduction in ELM divertor energy deposition. Thus, violations of this assumption can lead to large systematic errors in the inferred plasma data.

Physics Reports vol.312

First, one can build up a database by calculating the expected measured neutron signals for various plasma properties and experimental conditions. One is intrinsic rotation in the counter direction driven by the positive radial electric field near the plasma periphery, and the other is that in the co-direction driven by the ion temperature gradient at half of the plasma minor radius.

PACS: To this aim, during the last two years the materials of the plasma facing components PFCs have been replaced with the same combination foreseen in ITER, namely steady-state tokamak book combination of Be for the main wall and W for the divertor.

The absolute number and the energy spectrum of these neutrons is, in a somewhat complicated manner, related to the plasma conditions where the neutrons are being born. Therefore, the present article focuses mainly on the simulation and interpretation of neutron signals from D—D reactions and other fusion reactions are only briefly described for completeness.

A helical core distortion of steady-state tokamak book few cm forms and affects various core quantities, including plasma rotation, electron and ion temperature, and intrinsic W density. The width was found to be independent of conducted power, BT or q95 and insensitive to the SOL connection length.

The base mat and seismic pads on which the tokamak building will rest are under construction; the electrical yard is close to be finished and the ITER HQ building too. Clearly, the key assumption for extracting plasma parameters from neutron measurements is that the fast ions behave classically.

By comparing measured and calculated results in an iterative procedure, the values of the plasma parameters can be found for which consistency between the measurement and the physical assumptions can be achieved. Introduction 1. In the first part of this section, a brief overview over the fusion reactions, the cross sections, the calculation of fusion reactivities, spectra and the basic concepts used in neutron transport simulations is given.

However, on fusion experiments neutron detectors have to operate in somewhat unusual conditions for neutron physics and require the following additional specifications: 1.

Thirdly, there have to be computer codes for interpretation of the measurements. NIF, a Nd:Glass laser facility, has operated routinely at 1.With a number of next-step fusion devices currently being implemented — such as the International Thermonuclear Experimental Reactor (ITER) in Cadarache, France, and the National Ignition Facility (NIF) in Livermore, USA — and in view of the concomitant need to demonstrate the technological feasibility of fusion power plants as well as the economical viability of this method of energy.

Note: Citations are based on reference standards. However, formatting rules can vary widely between applications and fields of interest or study. The specific requirements or preferences of your reviewing publisher, classroom teacher, institution or organization should be applied.

Dumont R. Scenario development for the observation of alpha-driven instabilities in JET DT plasmas: 5 September Wednesday, 6 September Thursday, 7 September Friday, List of TMs on “Steady State Operation of Magnetic Fusion Devices”.

On alpha particle effects in tokamaks with a current hole The total alpha driven torque is found to oppose that generated by the neutral beam injection particles and to be an order of.

Sep 12,  · The DIII-D Advanced Tokamak (AT) program in the DIII-D tokamak [J. L. Luxon, Plasma Physics and Controlled Fusion Research,Vol.

I (International Atomic Energy Agency, Vienna, ), p. ] is aimed at developing a scientific basis for steady-state. The magnitude of tokamak plasma transport is found to be sensitive to the shape of the density profile: central peaking may be advantageous for high-temperature tokamak confinement.

For moderate-Q reactor operation, the present TFTR data base suffices to solve the three main steady-state reactor-plasma-physics problems of current drive.