Hostname: page-component-586b7cd67f-r5fsc Total loading time: 0 Render date: 2024-11-26T00:22:52.507Z Has data issue: false hasContentIssue false

Modifications of plasma edge electric field and confinement properties by limiter biasing on the KT-5C tokamak

Published online by Cambridge University Press:  13 March 2009

Hui Gao
Affiliation:
Department of Modern Physics, University of Science and Technology of China, Hefei, 230027, China
Kan Zhai
Affiliation:
Department of Modern Physics, University of Science and Technology of China, Hefei, 230027, China
Yi-Zhi Wen
Affiliation:
Department of Modern Physics, University of Science and Technology of China, Hefei, 230027, China
Shu-De Wan
Affiliation:
Department of Modern Physics, University of Science and Technology of China, Hefei, 230027, China
Chang-Xun Yu
Affiliation:
Department of Modern Physics, University of Science and Technology of China, Hefei, 230027, China

Abstract

Experiments using a biased multiblock limiter in the KT-5C tokamak show that positive biasing is more effective than negative biasing in modifying the edge electric field, suppressing fluctuations and improving plasma confinement. The biasing effect varies with the limiter area, the toroidal magnetic field and the biasing voltage. By positive biasing, the edge profiles of the plasma potential, the electron temperature and the density become steeper, resulting in a reduced edge particle flux, an increased global particle confinement time and lower fluctuation levels of the edge plasma.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1995

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Biglari, H., Diamond, P.H. & Terry, P.W. 1991 Influence of sheared poloidal rotation on edge turbulence. Phys. Fluids B 2, 14.CrossRefGoogle Scholar
Burrell, H. et al. 1989 Confinement physics of H-mode discharges in D III-D. Plasma Phys. Contr. Fusion 31, 16491664.CrossRefGoogle Scholar
Doerner, R. et al. 1994 Nucl. Fusion 34, 975.CrossRefGoogle Scholar
Field, A. R. et al. 1990 Proceedings of 18th EPS Conference, Berlin, Vol. 15C, Part III, p. 113.Google Scholar
Golant, V. E. 1983 Fundamental Plasma Physics, p. 332. Atomic Energy Press, Beijing (Chinese Translation).Google Scholar
Groebner, J. et al. 1989 Proceedings of 16th EPS Conference, Venice, Vol. 13B, Part I, p. 123.Google Scholar
Hinton, I. L. et al. 1991 Thermal confinement bifurcation and the L to H-mode transition in tokamaks. Phys. Fluids B 3, 696.CrossRefGoogle Scholar
Hutchinson, I. H. 1987 Principles of Plasma Diagnostics. Cambridge University Press.Google Scholar
Ida, K., Hidekuma, S., Miura, Y., Fujita, T., Mori, M., Hoshino, K., Suzuki, N., Yamauchi, T. & JFT-2M Group. 1990 Edge electric field profiles of H-mode plasmas in the JFT-2M tokamaks. Phys. Rev. Lett. 65, 13641367.CrossRefGoogle Scholar
Phillips, P. E. et al. 1987 Biasing experiments on TEXT. J. Nucl. Mater. 145–147, 807811.CrossRefGoogle Scholar
Rowan, W., Klepper, C., Ritz, C., Bengtson, R. D., Gentle, K. W., Phillips, P. E., Rhodes, T. L., Richards, B. & Wootton, A. J. 1987 Global particle confinement in the TEXAS experiment tokamak. Nucl. Fusion 27, 11051118.CrossRefGoogle Scholar
Shing, K. C. & Crume, E. C. 1989 Bifurcation theory of poloidal rotation in tokamaks: a model for the L-H transition. Phys. Rev. Lett. 63, 23692372.CrossRefGoogle Scholar
Statb, P. 1982 Probe measurements in the plasma boundary layer. J. Nucl.Mater. 111/112, 109122.CrossRefGoogle Scholar
Tagle, J.A. et al. 1991 Proceedings of 18th European Conference on Controlled Fusion and Plasma Physics, Vol. 15C, Part III, p. 93.Google Scholar
Takamura, S., Kinoshita, S. & Uesugi, Y. 1991 Formation of electric potential in a tokamak edge by limiter biasing. IEEE Trans. Plasma Sci. 19, 885893.CrossRefGoogle Scholar
Taylor, R. J., Brown, M. L., Fried, B. D., Grote, H., Liberati, J. R., Moraleg, G. J. & Pribyl, P. 1989 H-mode behavior induced cross-field currents in a tokamak. Phys. Rev. Lett. 63, 23652368.CrossRefGoogle Scholar
Tsushima, A., Mieno, T., Oertl, M., Hatakeyama, R. & Sato, N. 1986 Control of radial potential profile and nonambipolar ion transport in an electron cyclotron resonance mirror plasma. Phys. Rev. Lett. 56, 18151818.CrossRefGoogle Scholar
Tynan, G. R. et al. 1991 Proceedings of 18th European Conference on Controlled Fusion and Plasma Physics, Vol. 15C, Part III, p. 89.Google Scholar
Uesugi, Y., Yamakawa, Y. & Takamura, S. 1990 Control of the edge electric field by limiter biasing and electron beam injection in HYBTOK-Il tokamak. Research Using Small Tokamaks. IAEA, Vienna.Google Scholar
Wagner, F. et al. 1982 Regime of improved confinement and high beta in neutral-beam-heated divertor discharges of the ASDEX tokamak. Phys. Rev. Lett. 49, 14081412.CrossRefGoogle Scholar
Weynants, R. R. & Taylor, R. 1990 Dynamics of H-mode-like edge transitions brought about by external polarization. Nucl. Fusion, 30, 945949.CrossRefGoogle Scholar
Yang, S. K. et al. 1990 Edge conditions and turbulent fluctuations in the HL-I tokarnak. J. Nucl. Mater. 176/177, 699704.Google Scholar