On Use of Semiconductor Detector Arrays on COMPASS Tokamak

Semiconductor detector arrays are widely used in high-temperature plasma diagnostics. They have a fast response, which allows observation of many processes and instabilities in tokamaks. In this paper, there are reviewed several diagnostics based on semiconductor arrays as cameras, AXUV photodiodes (referred often as fast “bolometers") and detectors of both soft X-rays and visible light installed on the COMPASS tokamak recently. Fresh results from both spring and summer campaigns in 2012 are introduced. Examples of the utilization of the detectors are shown on the plasma shape determination, fast calculation of the radiation center, two-dimensional plasma radiation tomography in different spectral ranges, observation of impurity inflow, and also on investigation of MHD activity in the COMPASS tokamak discharges.

Authors:

• V. Weinzettl
• M. Imrisek
• J. Havlicek
• J. Mlynar
• D. Naydenkova
• P. Hacek
• M. Hron
• F. Janky
• D. Sarychev
• M. Berta
• A. Bencze
• T. Szabolics

Keywords:

• Bolometry
• plasma diagnostics
• soft X-rays
• tokamak.

References:

[1] R. Panek et al., "Reinstallation of the COMPASS-D Tokamak in IPP
ASCR", Czechoslovak Journal of Physics 56 (2006) B125-137.
[2] V. Weinzettl, et al., "Overview of the COMPASS diagnostics", Fusion
Engineering and Design 86 (2011) 1227-1231.
[3] D. F. Valcarcel, et al.. "An ATCA Embedded Data Acquisition and
Control System for the Compass tokamak". Fusion Engineering and
Design, 84 (2009) 1901-1904.
[4] D.F. Valcarcel, et al.. "Real-time software for the COMPASS tokamak
plasma control". Fusion Engineering and Design, 85 (2010) 470-473.
[5] F. Janky, et al., "Determination of the plasma position for its real-time
control in the COMPASS tokamak", Fusion Engineering and Design
86 (2011) 1120-1124.
[6] A. Szappanos et al., "EDICAM fast video diagnostic installation on the
COMPASS tokamak", Fusion Engineering and Design 85 (2010) 370-
373.
[7] V.Weinzettl, et al., "Design of multi-range tomographic system for
transport studies in tokamak plasmas", Nuclear Instruments and
Methods in Physics Research A 623 (2010) 806-808.
[8] J. Storrs, J. Dowling, G. Counsell, G. McArdle, "Real-time optical
plasma edge detection and position control on MAST", Fusion
Engineering and Design 81 (2006) 1841-1845.
[9] G. Hommen, et al., "Optical boundary reconstruction of tokamak
plasmas for feedback control of plasma position and shape", Review of
Scientific Instruments 81, 113504 (2010).
[10] Y. U. Nam, J. Chung, and Y. M. Jeon, "Estimation of plasma position
from tangentially viewed images on a toroidally symmetric device",
Review of Scientific Instruments 81, 093505 (2010).
[11] J. Mlynar, V. Weinzettl, G. Bonheure, A. Murari, JET-EFDA
Contributors: "Inversion Techniques in the Soft-X-Ray Tomography of
Fusion Plasmas: Toward Real-Time Applications", Fusion Science and
Technology, Vol. 58, No. 3, November 2010, p. 733-741.
[12] J. Mlynar, et al., "Introducing Minimum Fisher Regularisation
tomography to AXUV and soft X-ray diagnostic systems of the
COMPASS tokamak", Review of Scientific Instruments 83, 10E531
(2012).
[13] D. Naydenkova, et al., "The role of He in the tokamak COMPASS
discharges", submitted for publication in WDS Proceedings, 21st
Annual Student Conference - Week of Doctoral Students 2012, May 29-
June 1, 2012, Charles University in Prague, Czech Republic.
[14] M. Maraschek, "Control of neoclassical tearing modes", Nuclear Fusion
52 (2012) 074007.