RSI Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter UniPHY Group iResearch App Facebook

Review of Scientific Instruments / Volume 79 / Issue 10 / NUCLEAR PHYSICS, FUSION AND PLASMAS

Rev. Sci. Instrum. 79, 103505 (2008); http://dx.doi.org/10.1063/1.2981186 (8 pages)

A correlation electron cyclotron emission diagnostic and the importance of multifield fluctuation measurements for testing nonlinear gyrokinetic turbulence simulations a

a Based on a paper presented at the 17th Topical Conference on High-Temperature Plasma Diagnostics, Albuquerque, New Mexico, May 2008.
A. E. White1, L. Schmitz1, W. A. Peebles1, T. A. Carter1, T. L. Rhodes1, E. J. Doyle1, P. A. Gourdain1, J. C. Hillesheim1, G. Wang1, C. Holland2, G. R. Tynan2, M. E. Austin3, G. R. McKee4, M. W. Shafer4, K. H. Burrell5, J. Candy5, J. C. DeBoo5, R. Prater5, G. M. Staebler5, R. E. Waltz5, and M. A. Makowski6

1University of California-Los Angeles, Los Angeles, California 90095, USA
2University of California-San Diego, 9500 Gilman Dr, La Jolla, California 92093, USA
3University of Texas-Austin, Austin, Texas 78712, USA
4University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
5General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
6Lawrence Livermore National Laboratory, 3000 East Ave., Livermore, California 94550, USA

View MapView Map

(Received 30 June 2008; accepted 19 August 2008; published online 28 October 2008)

A correlation electron cyclotron emission (CECE) diagnostic has been used to measure local, turbulent fluctuations of the electron temperature in the core of DIII-D plasmas. This paper describes the hardware and testing of the CECE diagnostic and highlights the importance of measurements of multifield fluctuation profiles for the testing and validation of nonlinear gyrokinetic codes. The process of testing and validating such codes is critical for extrapolation to next-step fusion devices. For the first time, the radial profiles of electron temperature and density fluctuations are compared to nonlinear gyrokinetic simulations. The CECE diagnostic at DIII-D uses correlation radiometry to measure the rms amplitude and spectrum of the electron temperature fluctuations. Gaussian optics are used to produce a poloidal spot size with wo ∼ 1.75 cm in the plasma. The intermediate frequency filters and the natural linewidth of the EC emission determine the radial resolution of the CECE diagnostic, which can be less than 1 cm. Wavenumbers resolved by the CECE diagnostic are kθ ≤ 1.8 cm−1 and kr ≤ 4 cm−1, relevant for studies of long-wavelength turbulence associated with the trapped electron mode and the ion temperature gradient mode. In neutral beam heated L-mode plasmas, core electron temperature fluctuations in the region 0.5<r/a<0.9, increase with radius from ∼ 0.5% to ∼ 2%, similar to density fluctuations that are measured simultaneously with beam emission spectroscopy. After incorporating “synthetic diagnostics” to effectively filter the code output, the simulations reproduce the characteristics of the turbulence and transport at one radial location r/a = 0.5, but not at a second location, r/a = 0.75. These results illustrate that measurements of the profiles of multiple fluctuating fields can provide a significant constraint on the turbulence models employed by the code.

© 2008 American Institute of Physics

Article Outline

  1. INTRODUCTION AND MOTIVATION
  2. THE CORRELATION ELECTRON CYCLOTRON EMISSION DIAGNOSTIC
  3. CORRELATION ELECTRON CYCLOTRON EMISSION AT DIII-D, SYSTEM OVERVIEW
  4. TESTS AND CHARACTERIZATION OF THE CECE DIAGNOSTIC
    1. Beam waist measurements
    2. Calibration of the CECE radiometer
    3. Refractive effects
    4. Radial resolution of the CECE diagnostic
    5. Characterizing electronics noise and finite filter overlap
  5. CECE SYNTHETIC DIAGNOSTIC MODELING
  6. COMPARISON BETWEEN THE PROFILES OF TEMPERATURE AND DENSITY FLUCTUATIONS AND NONLINEAR GYROKINETIC SIMULATIONS
  7. CONCLUSIONS

RELATED DATABASES

To view database links for this article, you need to log in.

KEYWORDS and PACS

Keywords

plasma density, plasma diagnostics, plasma fluctuations, plasma radiofrequency heating, plasma simulation, plasma temperature, plasma transport processes, plasma turbulence

PACS

  • 52.70.Nc

    Particle measurements

  • 52.50.Qt

    Plasma heating by radio-frequency fields; ICR, ICP, helicons

  • 52.35.Ra

    Plasma turbulence

  • 52.25.Gj

    Fluctuation and chaos phenomena

  • 52.25.Fi

    Transport properties

  • 52.25.Tx

    Emission, absorption, and scattering of particles

ARTICLE DATA

Digital Object Identifier
http://dx.doi.org/10.1063/1.2981186

PUBLICATION DATA

ISSN

0034-6748 (print)  
1089-7623 (online)

Publisher

$abstract.society.value is a Member of CrossRef American Institute of Physics

For access to fully linked references, you need to log in.
    J. Wesson, Tokamaks, 3rd ed. (Clarendon, Oxford, UK, 2004), p. 150.

    J. Candy and R. E. Waltz, Phys. Rev. Lett. 91, 045001 (2003).

    G. R. McKee, R. Ashley, R. Durst, R. Fonck, M. Jakubowshi, K. Tritz, K. Burrell, C. Greenfield, and J. Robinson, Rev. Sci. Instrum. 70, 913 (1999)RSINAK000070000001000913000001.

    G. Cima, R. V. Bravenec, A. J. Wootton, T. D. Rempel, FL F. Gandy, C. Watts, and M. Kwon, Phys. Plasmas 2, 720 (1995)PHPAEN000002000003000720000001.

    S. Sattler, H. J. Hartfuss, and W. -A. Team, Phys. Rev. Lett. 72, 653 (1994).

    B. H. Deng, C. W. Domier, N. C. Luhmann, Jr., D. L. Brower, A. J. H. Donné, T. Oyevaar, and M. J. van de Pol, Phys. Plasmas 8, 2163 (2001)PHPAEN000008000005002163000001.

    M. E. Austin and J. Lohr, Rev. Sci. Instrum. 74, 1457 (2003)RSINAK000074000003001457000001.

    R. V. Bravenec and W. M. Nevins, Rev. Sci. Instrum. 77, 015101 (2006)RSINAK000077000001015101000001.

    M. W. Shafer, R. J. Fonck, G. R. McKee, and D. J. Schlossberg, Rev. Sci. Instrum. 77, 10F110 (2006)RSINAK00007700001010F110000001.

    A. E. White, L. Schmitz, G. R. McKee, C. Holland, W. A. Peebles, T. A. Carter, M. W. Shafer, M. E. Austin, K. H. Burrell, J. Candy, J. C. DeBoo, E. J. Doyle, M. A. Makowski, R. Prater, T. L. Rhodes, G. M. Staebler, G. R. Tynan, R. E. Waltz, and G. Wang, Phys. Plasmas 15, 056116 (2008)PHPAEN000015000005056116000001.

    C. L. Rettig, W. A. Peebles, J. Lohr, and M. E. Austin, Rev. Sci. Instrum.68, 484 (1997)RSINAK000068000001000484000001.


For access to citing articles, you need to log in.


Figures (11)

Access to article objects (figures, tables, multimedia) requires a subscription; log in to view available files.
(Access to supplementary files, where available, is free for this journal.)



Close

Google Calendar

ADVERTISEMENT

Your Recent History Recent History Help

Recently Viewed

  1. A correlation electron cyclotron emission diagnostic and the importance of multifield fluctuation measurements for testing nonlinear gyrokinetic turbulence simulations
  2. Low temperature plasma diagnostics with tunable synchrotron vacuum ultraviolet photoionization mass spectrometry
  3. High precision (14 bit), high density (octal) analog to digital converter for spectroscopy applications
  4. Diagnosis of high-intensity pulsed heavy ion beam generated by a novel magnetically insulated diode with gas puff plasma gun
  5. Four free parameter empirical parametrization of glow discharge Langmuir probe data
Go to AIP Home
Copyright © American Institute of Physics
close