Optimization of soft X-ray tomography on the COMPASS tokamak

• Autorzy: Imríšek M. , Mlynář J. , Löffelmann V. , Weinzettl V. , Odstrčil T. , Odstrčil M. , Tomeš M.

Identyfikatory

DOI

10.1515/nuka-2016-0066

• Konferencja: Summer School of Plasma Diagnostics PhDiaFusion 2015: “Soft X-ray Diagnostics for Fusion Plasma” (16-20.06.2015 ; Bezmiechowa, Poland)
• Języki publikacji: EN

Abstrakty

EN

The COMPASS tokamak is equipped with the soft X-ray (SXR) diagnostic system based on silicon photodiode arrays shielded by a thin beryllium foil. The diagnostic is composed of two pinhole cameras having 35 channels each and one vertical pinhole camera with 20 channels, which was installed recently to improve tomographic inversions. Lines of sight of the SXR detectors cover almost complete poloidal cross section of the COMPASS vessel with a spatial resolution of 1–2 cm and temporal resolution of about 3 s. Local emissivity is reconstructed via Tikhonov regularization constrained by minimum Fisher information that provides reliable and robust solution despite limited number of projections and ill-conditionality of this task. Improved border conditions and numerical differentiation matrices suppressing artifacts in reconstructed radiation were implemented in the code. Furthermore, a fast algorithm eliminating iterative processes was developed, and it is foreseen to be tested in real-time plasma control.

Słowa kluczowe

EN

soft X-ray; tomography; Tikhonov regularization; tokamak

• Wydawca: Institute of Nuclear Chemistry and Technology
• Czasopismo: Nukleonika
• Rocznik: 2016
• Tom: Vol. 61, No. 4
• Strony: 403--408
• Opis fizyczny: Bibliogr. 7 poz., rys.

Twórcy

autor

Imríšek M.

• Institute of Plasma Physics ASCR v.v.i., Faculty of Mathematics and Physics, Charles University in Prague, Za Slovankou 3, 18200 Praha 8, Czech Republic, Tel.: [phone]

autor

Mlynář J.

• Institute of Plasma Physics ASCR v.v.i., Faculty of Mathematics and Physics, Charles University in Prague, Za Slovankou 3, 18200 Praha 8, Czech Republic, Tel.: [phone]

autor

Löffelmann V.

• Institute of Plasma Physics ASCR v.v.i., Faculty of Mathematics and Physics, Charles University in Prague, Za Slovankou 3, 18200 Praha 8, Czech Republic, Tel.: [phone]

autor

Weinzettl V.

• Institute of Plasma Physics ASCR v.v.i., Faculty of Mathematics and Physics, Charles University in Prague, Za Slovankou 3, 18200 Praha 8, Czech Republic, Tel.: [phone]

autor

Odstrčil T.

• Optoelectronic Research Center, University of Southampton, University Rd, Southampton SO17 1BJ, United Kingdom

autor

Odstrčil M.

• Optoelectronic Research Center, University of Southampton, University Rd, Southampton SO17 1BJ, United Kingdom

autor

Tomeš M.

Bibliografia

• 1. Panek, R., Bilková, P., Fuchs, V., Hron, M., Chraska, P., Stockel, J., Urban, J., Weinzettl, V., Zajac, J., & Zacek, F. (2006). Reinstallation of the COMPASS-D tokamak in IPP ASCR. Czech. J. Phys., 56(Suppl. 2), B125–B137. DOI: 10.1007/s10582-006-0188-1.
• 2. Weinzettl, V., Naydenkova, D. I., Sestak, D., Vlcek, J., Mlynar, J., Melich, R., Jares, D., Malot, J., Sarychev, D., & Igochine, V. (2010). Design of multi-range tomographic system for transport studies in tokamak plasmas. Nucl. Instrum. Methods Phys. Res. Sect. AAccel. Spectrom. Dect. Assoc. Equip., 623, 806–808.DOI: 10.1016/j.nima.2010.04.010.
• 3. Anton, M., Weisen, H., Dutch, M. J., Linden, W., Buhlmann, F., Chavan, R., Marletaz, B., Marmillod, P., & Paris, P. (1996). X-ray tomography on the TCV tokamak. Plasma Phys. Control. Fusion, 38, 1849–1878. DOI: 10.1088/0741-3335/38/11/001.
• 4. Odstrcil, M., Mlynar, J., Odstrcil, T., Alper, B., Murari, A., & JET EFDA Contributors. (2012). Modern numerical methods for plasma tomography optimization. Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip., 686, 156–161.
• 5. Mazon, D., Vezinet, D., Pacella, D., Moreau, D., Gabelieri, L., Romano, A., Malard, P., Mlynar, J., Masset, R., & Lotte, P. (2012). Soft x-ray tomography for real-time applications: present status at Tore Supra and possible future developments. Rev. Sci. Instrum., 83(6), 063505. DOI: 10.1063/1.4730044.
• 6. Loffelmann, V., Mlynar, J., Imrisek, M., Mazon, D., Jardin, A., Weinzettl, V., & Hron, M. (2016). Minimum Fisher Tikhonov regularization adapted to real-time tomography. Fusion Sci. Technol., 69(2), 505–513.
• 7. Ingesson, L. C., Alper, B., Peterson, B. J., & Vallet, J. -C. (2008). Tomography diagnostics: Bolometry and soft X-ray detection. Fusion Sci. Technol., 53(2), 528–576.

Uwagi

PL

Opracowanie ze środków MNiSW w ramach umowy 812/P-DUN/2016 na działalność upowszechniającą naukę.