TITLE

Performance of the microwave reflectometry diagnostic for density profile measurements on ASDEX Upgrade

AUTHOR(S)
Silva, A.; Manso, M.; Vergamota, S.; Cupido, L.; Meneses, L.; Nunes, I.
PUB. DATE
January 2001
SOURCE
Review of Scientific Instruments;Jan2001, Vol. 72 Issue 1, p307
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The broadband reflectometry system on ASDEX Upgrade is now routinely providing electron density profiles with a minimum temporal spacing of 30 μs. The plasma is probed from zero density to n[sub e]=6.64×10[sup 19] m[sup -3] at the low field side with combined O and X modes, and from n[sub e]=0.318×10[sup 19] to n[sub e]=6.64×10[sup 19] m[sup -3] at the high field side using O mode. Here we analyze the performance of the diagnostic for profile measurements taking into account its design options and the experimental results obtained in a wide range of plasma regimes. We address several questions, in particular the measuring range of the antennas and the range of density gradients. It is shown that it is possible to obtain a detailed evolution of the density profile and density gradient even in the presence of turbulence, providing that sufficient data can be extracted from the plasma. The radial movements of the plasma can be measured with great accuracy, which is especially important for the use of reflectometry for plasma position control, as is proposed for the International Thermonuclear Experimental Reactor. The experimental results demonstrate that the frequency modulation of a continuous wave reflectometry system on ASDEX Upgrade can provide reliable and accurate density profile measurements at both sides of the plasma with automatic analysis. © 2001 American Institute of Physics.
ACCESSION #
4716914

 

Related Articles

  • High resolution measurements of neutral density and ionization rate in the Alcator C-Mod tokamak. Boivin, R. L.; Hughes, J. W.; LaBombard, B.; Mossessian, D.; Terry, J. L. // Review of Scientific Instruments;Jan2001, Vol. 72 Issue 1, p961 

    Two new high resolution detectors have been installed on the Alcator C-Mod tokamak to measure the neutral density and ionization rate at the edge of the main chamber plasma. Using a silicon detector sensitive to UV light, and a very narrow filter with transmission peaking at 1216 Ã…, the...

  • Ultrashort pulse reflectometry for electron density profile measurements on SSPX. Roh, Y.; Domier, C. W.; Luhmann, N. C. // Review of Scientific Instruments;Jan2001, Vol. 72 Issue 1, p332 

    A broadband ultrashort pulse reflectometry (USPR) diagnostic has been developed for measuring electron density profiles of the sustained spheromak physics experiment (SSPX) device. In USPR, an extremely short pulse or chirped wave form is propagated which contains a broad range of frequency...

  • The ten-channel pulsed radar reflectometer at the TEXTOR-94 tokamak. van Gorkom, J. C.; van de Pol, M. J.; Donné, A. J. H. // Review of Scientific Instruments;Jan2001, Vol. 72 Issue 1, p336 

    A new ten-channel pulsed radar reflectometer has been taken into operation at the Torus Experiment for Technology Oriented Research-94. The system will be used simultaneously as a density profile and as a density fluctuation diagnostic. Ten density layers from 0.4×10[sup 19] to 4×10[sup...

  • Simulation of reflectometry density changes using a 2D full-wave code. da Silva, F.; Manso, M.; Silva, A. // Review of Scientific Instruments;Jan2001, Vol. 72 Issue 1, p311 

    Broadband reflectometry is used to obtain density profiles in fusion plasmas using waves reflected at different plasma layers. The reflected signal can be severely affected by plasma fluctuations and/or fast density changes. In order to understand the plasma response, a finite difference time...

  • Asymmetric double Langmuir probe: Small signal application. Uckan, Taner // Review of Scientific Instruments;Dec1987, Vol. 58 Issue 12, p2260 

    We discuss the asymmetric double Langmuir probe (ADLP) and demonstrate the possibility of using it to measure plasma temperature Te and density n when it is operated in the region of small signal response. The area of one of the ADLP collectors is considerably larger than the other. This probe...

  • X-mode heterodyne reflectometer for edge density profile measurements on Tore Supra. Clairet, F.; Sabot, R.; Bottereau, Ch.; Chareau, J. M.; Paume, M.; Heuraux, S.; Colin, M.; Hacquin, S.; Leclert, G. // Review of Scientific Instruments;Jan2001, Vol. 72 Issue 1, p340 

    A new broadband reflectometer operating in the frequency range 50–75 GHz in extraordinary mode polarization has been developed and tested on Tore Supra to measure edge density profiles. Using solid state source and active frequency multipliers, it performs routine measurements in 20...

  • Doppler reflectometry for the investigation of propagating density perturbations. Hirsch, M.; Holzhauer, E.; Baldzuhn, J.; Kurzan, B. // Review of Scientific Instruments;Jan2001, Vol. 72 Issue 1, p324 

    In a Doppler reflectometry experiment the line of sight is chosen to be nonperpendicular with respect to the reflecting layer. This type of diagnostic is able to probe density perturbations with the wave number in the reflecting layer selected by the tilt angle. The propagation velocity of the...

  • Microwave reflectometry for turbulence studies on ASDEX upgrade (abstract). Ribeiro, T. T.; Serra, F.; Manso, M. E.; Vergamota, S.; Cupido, L.; Silva, A.; Conway, G. D.; Ryter, F.; Suttrop, W. // Review of Scientific Instruments;Jan2001, Vol. 72 Issue 1, p319 

    The reflectometry system installed in the tokamak ASDEX Upgrade has 11 channels primarily aimed at profile measurements and two dedicated channels operating at fixed frequency to study density fluctuations. The channels used for profile measurements can also be operated at fixed frequency. In...

  • Refiectometry on ITER and ITER Joint Central Team and Home Teams Vayakis, G.; Bretz, N.; Doyle, E.; Vershkov, V. A.; Donne, A. J. H.; Irby, J.; Mase, A.; Sanchez, J.; Shevchenko, V. F.; Walker, C. I. // Review of Scientific Instruments;Jan1997, Vol. 68 Issue 1, p435 

    Focuses on the use of reflectometry on the International Thermonuclear Experimental Reactor to measure the density profile in the main plasma and the divertor and to provide measurements of the plasma position and shape supplementary to the magnetic diagnostics. Systems required to access the...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics