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  • 11
    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
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  • 12
    Electronic Resource
    Electronic Resource
    The Atmosphere of Mars (1974)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 2 (1974), S. 333-367 
    Details
    ISSN: 0084-6597
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Geosciences , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.ea.02.050174.002001
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  • 13
    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
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  • 14
    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
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  • 15
    Electronic Resource
    Electronic Resource
    Photon recycling system for multiposition tangential Thomson scattering : Proceedings of the tenth topical conference on high temperature plasma diagnostics (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 501-503 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Multiposition tangential Thomson scattering makes it possible to measure the profiles of the local drift velocity and current density of a tokamak plasma. To achieve a reasonably small observational error (20%) a high photon yield is required. In this paper we propose an optical system to increase the photon yield by about a factor of 7. Photons from a pulsed ruby laser are captured in a ring cavity by means of an electro-optical switch. The trapped laser beam recirculates about 14 times through the sampling volume which is part of the cavity, increasing the laser energy of 25 J to an effective energy of about 140 J. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146330
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  • 16
    Electronic Resource
    Electronic Resource
    High-resolution multiposition Thomson scattering for the TJ-II stellarator : 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. 763-767 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: In this article, the recent installed multiposition Thomson scattering (TS) of the TJ-II stellarator is presented. Light from a pulsed ruby laser is scattered by the free electrons of the plasma and led to a spectrometer for spectral analysis. The Doppler broadened spectrum of the scattered light is analyzed with a spectrometer in the Littrow configuration, detected with a GaAsP image intensifier and recorded with two intensified charged coupled device cameras. Values of the electron temperature (Te) in the range of 50 eV up to 4 keV can be measured at 160 spatial elements of 2.25 mm along a chord of 360 mm. First results show that the observational error for Te is close to the expected error of ∼10% at an electron density (ne) of 1×1019 m−3 using a laser energy of 8 J. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149399
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  • 17
    Electronic Resource
    Electronic Resource
    Determination of the local current density by means of tangential Thomson scattering: Experimental setup, feasibility test, and preliminary observations (1989)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 60 (1989), S. 2673-2679 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The local current density is one of the most important and most difficult parameters to be determined in a thermonuclear plasma. An experimental setup to measure the local electron drift velocity and thus, the current density, by means of tangential Thomson scattering, is presented. The drift velocity of the plasma causes a small wavelength shift of the scattered spectrum, which will be proportional to the local current density if toroidal ion rotation can be neglected. The ratio between the drift velocity and the mean thermal electron velocity is small, typically ∼0.05. A 20-channel high transmission polychromator has been constructed to observe the electron temperature and density within an accuracy of 1% and the drift velocity within 20% at a plasma density ne≈5×1019 m−3 and a laser energy of 7 J. A feasibility test on radial scattering shows that there is good agreement between the accuracy obtained from quantum statistics and observations, respectively. The high transmission and relatively high resolution of the polychromator enable the observation of irregularities in the velocity distribution which should be taken into account in the determination of the drift velocity. Preliminary observations in the tangential direction demonstrate the possibility to determine the drift velocity by a single laser shot. At ne ≈6×1019 m−3 and a laser energy of 3.5 J in the scattering volume a wavelength shift of −2.5±0.5 nm has been recorded corresponding to jφ≈1×107 A/m2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1140692
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  • 18
    Electronic Resource
    Electronic Resource
    PROMT: A multiposition Thomson-scattering system for RTP : Proceedings of the 9th topical conference on high temperature plasma diagnostics (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 4947-4949 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: PROMT is a system for multiposition Thomson scattering in use at the Rijnhuizen Tokamak Project tokamak. Light from a ruby laser is scattered by the free electrons in the plasma and is collected along a vertical chord of 180 mm. Electron temperature and density profiles can be measured resolving up to 36 spatial elements. Scattered light is spectrally analyzed by a Littrow polychromator and subsequently detected with an intensified charge coupled device camera. At densities of 2×1019 m−3 electron temperatures in the range of 50 eV–3 keV can be measured with an accuracy of ∼5%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1143506
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  • 19
    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
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  • 20
    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
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