Library

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
    Amsterdam : Elsevier
    Physics Letters A 43 (1973), S. 527-528 
    ISSN: 0375-9601
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 59 (1988), S. 1509-1511 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A simple experimental procedure used in the TJ-I tokamak, for simultaneously measuring the ion temperature is described. Two monochannel systems (neutral and optical) are scanned at a preprogrammed time of the tokamak discharge, where the signals are stationary. System performances are illustrated with results obtained in the TJ-I tokamak.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 4617-4617 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A nonintrusive method to measure low level stochastic electric fields in hot plasmas is being investigated in the TJ-I tokamak (R=30 cm, a=10 cm, Ip〈60 kA, BT〈1.5 T). It is based on the measurement of ion temperature of particles with different masses, i.e., protons and impurities, by the Doppler line width of their emission lines. It is hypothesized that its difference is due to gross mass motion produced by E˜×B. As a guide for data interpretation, we compare our results with typical values of fluctuating electric fields obtained by Langmuir probes at the plasma periphery. The ion temperatures of representative impurities like C V and O V, have been measured by the Doppler line width of near UV lines 2271 and 2781 A(ring), respectively. The proton temperature has been measured analyzing the Hβ and Hα line wings whose emission is due to highly energetic neutrals. Results of fluctuating electric fields obtained by this method as a function of radius and plasma density will be presented. The deduced fluctuating electric fields are higher at the plasma periphery than at the plasma center and in the latter much higher at low than at high densities. An approach to distinguish between radial and poloidal electric field fluctuations is being addressed by modeling experimental results with a simulation code.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 312-315 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We describe a vacuum ultraviolet spectrometer having spatial, spectral, and temporal resolution capabilities that is being built as a diagnostic for the TJ-II flexible heliac device. The system is based around a renovated 0.5 m radius Rowland circle grazing incidence duochromator and will cover the wavelength range from 300 to 2000 Å with good spatial resolution. A toroidal mirror used at grazing incidence, mounted on a specially designed mounting positioned between the plasma and spectrometer, will permit ∼80% of the bean shaped plasma cross section to be scanned with spatial resolution on the order of 10 mm. In addition, filters and slits are incorporated to tailor the incident light beam. The duochromator was coupled directly to the TJ-II during the machine start up phase to check the good operation of the duochromator. These data have been fed back into the design program in order to optimize the instrument design. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 2580-2584 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The performance of an original VUV filter spectrometer with spatial resolution is illustrated with typical applications as a plasma diagnostic. The spectrum of the total radiated power obtained in the TJ-I tokamak, the observation of flattenings on radiation profiles associated with magnetic islands, and the determination of particle confinement times in laser blow-off impurity injection experiments are highlighted.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A spectroscopic method to directly measure the nonthermal velocity fluctuations is being studied in the TJ-I tokamak. The method is based on converting velocity in intensity fluctuations by subtracting the signals received at two symmetric positions of a spectral emission line. This is accomplished by means of a multichannel detector in which the channels respond to the line intensity at different wavelengths and positions within a single spectral line. A multichannel plate photomultiplier, with an anode split in 8×8 parts, is optically coupled by means of an anamorphic optical system, to the focal plane of a 1 m spectrometer where the image of a spectral line is formed. Some individual anodes are grouped to configurate four acquisition channels which are fled into four current amplifiers. The 100 kHz bandwidth signals are stored in a digital oscilloscope connected to a VAX computer, where the signals are processed. A simple simulation allows us to relate the differential signal between symmetrical channels to velocity in cases where the radial extension of the emitting ion is comparable to the radial correlation length of the turbulence causing the velocity fluctuations. The influence of the detection statistics on the measurement is analyzed. Preliminary results obtained in the TJ-I tokamak, using this system, will be presented. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 534-536 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A comparative study of several luminescent materials which have potential interest for broadband plasma radiation detectors covering the vacuum ultraviolet (VUV) and x-ray ranges has been carried out. Among the studied phosphors Y2O2S:Tb (P-45) exhibits the highest sensitivity, which has been seen to be more than one order of magnitude higher than the standard VUV phosphor-sodium salicylate, over the whole spectral range. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 5196-5198 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A code for calculating the actual spectral line shapes in magnetically confined plasmas of the tokamak type is described. The code determines the resulting line shape averaged along the line-of-sight of the spectrometer, starting from prescribed thermal temperature, ion emissivity, and flow profiles, for a plasma immersed in a magnetic field. In addition, the influence on the impurity linewidths of nonthermal fluctuating velocities due to fluctuating electric fields and to possible magnetic fluctuations is also included. Typical applications of the code to spectral data analysis in the TJ-I tokamak are given.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 504-504 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The precise measurement of the power absorption in some ECRH plasma experiments can be plagued with many practical problems, which makes the direct validation of any theoretical model difficult. In the present work, the feasibility of a method to directly measure the electric field at the predicted resonant position is carried out. From the electric field it is possible to compute the local density power carried by the microwave beam and, hence, deduce the power deposition profile. The method based on measuring the ratio of near and far satellite intensities of He I lines, already used in cold plasma discharges,1 presents challenging problems when applied to a hotter plasma. The electric field is estimated using ray tracing calculations in the TJ-IU torsatron. The field is locally obtained in the plasma from the dispersion relation and the estimations for the injected power (200 kW) show that the effect of the microwave field can be non-negligible on the He I lines. An experimental setup to explore this idea in the TJ-IU torsatron will be described. The low densities of this device and the use of a signal-to-noise subtraction technique make this method feasible according to our preliminary estimation. The difficulties encountered and the results obtained will be reported.© 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 680-682 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We outline designs for several rare-earth-based phosphor powder detector systems for monitoring the broadband VUV plasma radiation in the TJ-II torsatron device. These include a global radiation detector, a detector with temporal and spectral resolution, and a third with radial scanning capabilities. We describe the selection of a phosphor powder for this application having good response from the soft x ray to the VUV, a fast response time, and the capability of operation at high temperatures. In addition, we give details of a method developed in-house for depositing thin uniform layers of powder on glass substrates for use as phosphor screens. Finally, we present some detector test results obtained in the plasma of the TJ-I U torsatron. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...