GLORIA

GEOMAR Library Ocean Research Information Access

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
Filter
Document type
Publisher
Years
  • 1
    Electronic Resource
    Electronic Resource
    Technique for relating internal plasma shape to plasma current profiles in noncircular tokamaks : Eighth topical conference on high−temperature plasma diagnostics (1990)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 3301-3303 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A tangentially viewing soft x-ray pinhole camera has been used to measure internal plasma shape on the PBX-M tokamak. While several methods of deriving the poloidal emissivity profile have been investigated, the most robust consists of a forward modeling technique which permits the inference of the internal shape, axial safety factor, and the current profile. Using poloidal flux measurements to constrain the external shape, equilibria are calculated for different values of q(0). The mapping of the x-ray emissivity to the internal poloidal flux value is obtained by Abel-inverting the x-ray image on the plasma midplane and assuming constant emissivity on a flux surface. Model camera images are then constructed and compared with the measured camera image. A least-squares fit of these models to the measured image produces an inferred value of q(0). The effects of noise have been examined, and the resulting uncertainty in q(0) can range from 0.1 to 0.3, depending on details of the experimental conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1141620
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Charge exchange recombination spectroscopy measurements of ion temperature and plasma rotation in PBX (1985)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 56 (1985), S. 865-867 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The primary diagnostic on PBX for ion temperature measurements is charge exchange recombination spectroscopy of low Z ions, wherein fast neutrals from the heating neutral beams excite spectral lines from highly excited states (n〉4) of hydrogenic O, C, and He via charge exchange collisions with the respective fully stripped ions. Since the neutral beams on PBX provide relatively low-velocity neutrals (i.e., D° beams at 44 keV), best signals are obtained using the near-UV lines of O7+ (e.g., n=8–7, 2976 A(ring)). Off-line analysis of the Doppler broadened and shifted line profiles includes nonlinear least-squares fitting to a model line profile, while a simplified on-line fast analysis code permits between-shot data analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1138075
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Tomographic imaging of MHD activity in tokamaks by combining diode arrays and a tangentially viewing pinhole camera (1988)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 59 (1988), S. 1819-1821 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Two 32-channel side-viewing soft x-ray diode arrays will be installed on PBX-M which will provide profile information in the horizontal and vertical directions with a time resolution up to 1 μs. The information from these arrays can be reconstructed to provide a high time-resolution poloidal emission profile using a maximum-entropy-based technique which incorporates the reconstructed profile from a tangentially viewing soft x-ray pinhole camera. The pinhole camera provides lower time-resolution (about 5 ms) shape information which has been reconstructed with the assumption of toroidal symmetry. The pinhole camera information supplements the information from the diode arrays, allowing a reconstruction which can resolve MHD fluctuations of the equilibrium profile. The pinhole camera information need only be a better approximation to the real emission profile than the assumption of a flat profile since the algorithm uses it as a first-order solution which is perturbed by the information from the diode arrays. The algorithm can also explicitly include the bean-shaped PBX-M vacuum vessel and the vignetting of some detectors by the pusher coil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1140070
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Soft-x-ray camera for internal shape and current-density measurements on a noncircular tokamak (1988)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 59 (1988), S. 1831-1833 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A two-dimensional, tangentially viewing, soft-x-ray pinhole camera has been fabricated to provide internal shape measurements on the PBX-M tokamak. It consists of a scintillator at the focal plane of a foil-filtered pinhole camera, which is, in turn, fiber-optically coupled to an intensified framing video camera (Δt≥3 ms). Automated data acquisition is performed on a stand-alone image processing system, and data archiving and retrieval take place on an optical disk video recorder. The derivation of the poloidal emission distribution from the measured image is done by fitting to model profiles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1140074
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Control of plasma shape and performance of the PBX-M tokamak experiment in high-βt /high-βp regimes (1990)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 2 (1990), S. 1271-1279 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The highly indented plasmas of the PBX-M tokamak experiment [Plasma Physics and Controlled Nuclear Fusion Research (IAEA, Vienna, 1989), Vol. 1, p. 97] have reached plasma regimes of both high volume-averaged beta (βt), and high-beta poloidal (βp), and show evidence of the suppression of external surface modes by the passive stabilizing system. Values of βt up to 4.0 I/aB (% MA/m T) with Ti(0)≈4 keV have been obtained. A magnetohydrodynamic analysis of plasmas with βp=2.0 indicates that these plasmas are near the threshold of the second stability regime. A value of βt of 6.8% has been reached with Ti(0)〉5 keV and an indentation of 28%. Control of plasma shape is accomplished with a feedback system that uses a moment expansion about a single equilibrium and is augmented by time-dependent waveforms to redefine plasma shape. Diagnostics to measure the safety factor q have been developed and used to make accurate measurements of q(r) and to verify changes made in q(0).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.859542
    Location Call Number Limitation 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...