Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Error analysis of Rijnhuizen tokamak project Thomson scattering data (1999)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 1999-2011 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: At the Rijnhuizen tokamak project a double pulse multiposition Thomson scattering diagnostic has been operational since 1996. It has been installed for the study of small scale structures in electron temperature (Te) and density (ne). This diagnostic measures Te and ne with high spatial resolution (3 mm full width at half maximum, i.e., 2% of the minor radius) and high accuracy (3%–4% of Te and 2%–3% of ne in the range of 50 eV–6 keV and ne=5×1019 m−3.) In this article an extensive error analysis is performed on both statistical and systematic deviations. It is found that the instrument function of the detection branch has a smoothing effect on the noise. This reduces the statistical error on the Te and ne measurements on each spatial position, because the resolution of the instrument is oversampled. The long tail of the instrument profile of the entire diagnostic has a significant effect on the systematic deviations in the Te and ne determination. However, it does not affect the relative size of the small scale structures on Te and ne, and for this this reason does not hamper the study of these structures. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149702
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Tokamak plasmas with dominant electron cyclotron heating; evidence for electron thermal transport barriers (1999)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 6 (1999), S. 4645-4657 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In the Rijnhuizen Tokamak Project [RTP, A. J. H. Donné, the RTP Team, Plasma Phys. Rep. 20, 192 (1994)], experiments have been carried out with Electron Cyclotron Heating (ECH) at four to seven times the Ohmic power, with a deposition width 〈10% of the minor radius. Central deposition leads to sharp electron temperature (Te) gradients near the q=1 surface. Off-axis deposition results in steady-state hollow Te profiles. A radial scan of the ECH deposition reveals a discrete, stepwise response of Te profile. The transitions occur for a displacement of the deposition by less than 1 mm. Each transition is due to the loss of a transport barrier. The transitions occur when the minimum value of q passes through the values 1, 4/3, 5/2, 2, 7/2 and 3. A numerical model featuring transport barriers near those q values gives good reproduction of the experimental data. The possible role of the topological properties of the magnetic field is discussed. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.873751
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Steady state off-axis sawtoothing in the Rijnhuizen Tokamak project (1999)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 6 (1999), S. 3898-3905 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A family of off-axis, or annular, instabilities has been studied using Thomson scattering, soft X-ray emission, and two electron cyclotron emission diagnostic systems. In the Rijnhuizen tokamak (RTP) [N. J. Lopes Cardozo et al., Plasma Physics and Controlled Nuclear Fusion Research 1992 (International Atomic Energy Agency, Vienna, 1993), Vol. 1, p. 271] these phenomena are invoked in a controlled way in discharges with specific (off-axis) deposition of electron cyclotron heating (ECH) and persist during most of the heating period, or during many current diffusion times. Based on coherent mode analysis at the crash time, the instabilities are associated with resonant surfaces near simple rational values of q (〈fraction SHAPE="CASE"〉32, 2, and 3). A parameter study shows an increase of reheat rate and a decrease of sawtooth period with increasing ECH power and — in contrast to observations in other experiments — with increASING density as well. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.873652
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    High density, high performance high-confinement-mode plasmas in the Joint European Torus (JET) : Review,Tutorial and Invited Papers from the 43rd Annual Meeting of the APS Division of Plasma Physics (2002)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 9 (2002), S. 2103-2112 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Recent experiments at the Joint European Torus [Rebut et al., Fusion Eng. Des. 22, 7 (1993)] aim to improve confinement quality in high-confinement-mode (H-mode) plasmas at high densities. Energy confinement time as predicted by the International Thermonuclear Experimental Reactor ITER-H98(y,2) scaling at densities near or in excess of 85% of the Greenwald density limit scaling has been obtained by (i) strong plasma shaping (triangularity 0.35〈δ〈0.5), or (ii) impurity seeding, or (iii) high-field side pellet injection. Slow peaking of central density without confinement degradation is observed. Loss of sawteeth and core impurity accumulation is prevented by central ion cyclotron resonance heating. In high triangularity and impurity seeded plasmas, reduction of average power loss associated with type I edge localized modes (ELMs) is found which is attributed to the occurrence of additional losses in between ELMs. Broad band magnetic fluctuations are seen which are reminiscent of regimes with small ELMs in other tokamaks. Plasma configurations have been varied to find best combinations of edge pedestal parameters and small ELM losses. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1456067
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Structures in Te profiles: High resolution Thomson scattering in the Rijnhuizen tokamak project : Proceedings of the 12th topical conference on high temperature plasma diagnostics (1999)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 995-997 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: In the Rijnhuizen tokamak project, the double pulse multiposition Thomson scattering diagnostic is in full operation. Its high spatial resolution enables the measurement of small scale structures in Te, ne, and pe. Thomson scattering profiles during an ordinary sawtooth crash show the displacement of the hot core in great detail. Measurements on off-axis sawtoothing plasmas show that a small central part remains unaffected. Filaments are observed in plasmas which show a transient central temperature rise in response to fast edge cooling. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149366
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    A high resolution multiposition Thomson scattering system for the Rijnhuizen Tokamak Project (1997)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 3380-3392 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A high resolution multiposition Thomson scattering setup to measure the electron temperature (Te) and density (ne) of a hot plasma is described. The system is operational at the Rijnhuizen Tokamak Project. Light from a high power pulsed ruby laser is scattered by the free plasma electrons and relayed to a Littrow polychromator for spectral analysis. The spectrally and spatially resolved light is detected by a GaAsP photocathode. The two-dimensional image is intensified and recorded with a charge-coupled device camera.Te in the range of 50 eV–6 keV can be measured at 115 spatial elements of 2.6 mm length along the laser beam. The observation error is 〈6% at ne=2×1019 m−3 and smaller for higher ne. The high resolution and accuracy enabled the observation of small scale structures in Te and ne. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148345
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Double pulse Thomson scattering system at RTP : Proceedings of the eleventh topical conference on high temperature plasma diagnostics (1997)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 721-724 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: In this article a double pulse multiposition Thomson scattering diagnostic, under construction at RTP, is discussed. Light from a double pulsed ruby laser (pulse separation: 10–800 μs, max. 2×12.5 J) is scattered by the free electrons of the tokamak plasma and relayed to a Littrow polychromator for spectral analysis. The spectrally resolved light is recorded by two ICCD detectors. Simulations show that the system sensitivity will be such that electron temperatures in the range of 100 eV–7 keV can be determined with an accuracy as good as 2%–3% for electron densities of 1020 m−3, with a spatial resolution down to 2.6 mm. With this diagnostic the dynamics of small scale structures in the electron temperature profile will be studied. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1147685
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Calibration procedure and data processing for a TV Thomson scattering system (2001)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 72 (2001), S. 3514-3527 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Calibration procedures for Thomson scattering systems based on television-like cameras, so-called TVTS systems, are described. The TVTS systems of the Rijnhuizen Tokamak Project (RTP), the TJ-II stellarator, and the Torus Experiment for Technology Oriented Research (TEXTOR) tokamak combine a 10–15 J ruby laser as a source with an intensified charge coupled device camera as a detector. A tungsten strip lamp in combination with an integrating sphere is used to calibrate all ∼105 pixels of the camera relatively to each other. Rayleigh scattering on hydrogen or nitrogen is used to perform an absolute calibration of the complete detection system. Great emphasis is placed on possible systematic errors on the determination of the electron temperature Te and density ne due to the calibration, such as tungsten lamp temperature, detoriation of the detection window, long term stability, laser beam alignment, and detector linearity. The long term stability of the system was tested by comparing different sets of calibration factors. Over a period of 1/2 yr the values of the calibration factors varied by less than 5%. Using the same Thomson scattering data but different sets of calibration factors the Te values varied even less than 1%. A two camera technique was used to search for possible unknown systematic errors in the determination of Te profiles. It appears that these systematic errors are about half of the observational error on Te. Density fluctuations can be determined with an accuracy equal to the statistical error of ∼3%, while the systematic error on ne appeared to be ∼10%, which can be corrected for using interferometer data. As a result, these TVTS systems can measure Te and ne profiles with ∼100 (RTP) or 120 (TEXTOR) spatial elements along the full plasma diameter with observational errors on Te of ∼6% in the range of 25 eV–6 keV, at ne=2×1019 m−3 and 10 J laser energy. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1386896
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...