Beam emission spectroscopy turbulence imaging system for the MAST spherical tokamak

A. R. Field, D. Dunai, R. Gaffka, Y. C. Ghim, I. Kiss, B. Mészáros, T. Krizsanóczi, S. Shibaev, S. Zoletnik

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

A new beam emission spectroscopy turbulence imaging system has recently been installed onto the MAST spherical tokamak. The system utilises a high-throughput, direct coupled imaging optics, and a single large interference filter for collection of the Doppler shifted D emission from the ∼2 MW heating beam of ∼70 keV injection energy. The collected light is imaged onto a 2D array detector with 8 × 4 avalanche photodiode sensors which is incorporated into a custom camera unit to perform simultaneous 14-bit digitization at 2 MHz of all 32 channels. The array is imaged at the beam to achieve a spatial resolution of ∼2 cm in the radial (horizontal) and poloidal (vertical) directions, which is sufficient for detection of the ion-scale plasma turbulence. At the typical photon fluxes of ∼10 11 s -1 the achieved signal-to-noise ratio of ∼300 at the 0.5 MHz analogue bandwidth is sufficient for detection of relative density fluctuations at the level of a few 0.1%. The system is to be utilised for the study of the characteristics of the broadband, ion-scale turbulence, in particular its interaction with flow shear, as well as coherent fluctuations due to various types of MHD activity.

Original languageEnglish
Article number013508
JournalReview of Scientific Instruments
Volume83
Issue number1
DOIs
Publication statusPublished - Jan 2012

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Emission spectroscopy
Imaging systems
Turbulence
Plasma turbulence
turbulence
Avalanche photodiodes
Analog to digital conversion
Ions
Shear flow
Magnetohydrodynamics
spectroscopy
Optics
Signal to noise ratio
plasma turbulence
Photons
Cameras
Throughput
Fluxes
Detectors
Bandwidth

ASJC Scopus subject areas

  • Instrumentation

Cite this

Beam emission spectroscopy turbulence imaging system for the MAST spherical tokamak. / Field, A. R.; Dunai, D.; Gaffka, R.; Ghim, Y. C.; Kiss, I.; Mészáros, B.; Krizsanóczi, T.; Shibaev, S.; Zoletnik, S.

In: Review of Scientific Instruments, Vol. 83, No. 1, 013508, 01.2012.

Research output: Contribution to journalArticle

Field, AR, Dunai, D, Gaffka, R, Ghim, YC, Kiss, I, Mészáros, B, Krizsanóczi, T, Shibaev, S & Zoletnik, S 2012, 'Beam emission spectroscopy turbulence imaging system for the MAST spherical tokamak', Review of Scientific Instruments, vol. 83, no. 1, 013508. https://doi.org/10.1063/1.3669756
Field, A. R. ; Dunai, D. ; Gaffka, R. ; Ghim, Y. C. ; Kiss, I. ; Mészáros, B. ; Krizsanóczi, T. ; Shibaev, S. ; Zoletnik, S. / Beam emission spectroscopy turbulence imaging system for the MAST spherical tokamak. In: Review of Scientific Instruments. 2012 ; Vol. 83, No. 1.
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