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Heat transport analysis of the improved confinement discharge with LHW in the HT-7 tokamak

Published online by Cambridge University Press:  15 December 2009

X. M. ZHANG ,
X. SHEN ,
B. N. WAN ,
Z. W. WU  and
J. FU
X. M. ZHANG
Affiliation:
Department of Physics, East China University of Science and Technology, Shanghai 200237, China ([email protected], [email protected])
X. SHEN
Affiliation:
Department of Physics, East China University of Science and Technology, Shanghai 200237, China ([email protected], [email protected])
B. N. WAN
Affiliation:
Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031, China
Z. W. WU
Affiliation:
Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031, China
J. FU
Affiliation:
Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031, China
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Abstract

In the HT-7 tokamak, heat transport analysis is carried out for the lower hybrid current drive (LHCD) experiments. Electrons and ions are coupled and good confinement can be obtained by properly optimizating LHCD and plasma parameters. Under the conditions that the plasma current is about 220 kA, the lower hybrid wave (LHW) power is about 300 kW and the central line-averaged density is about 1.5×1013 cm−3, lower hybrid wave power deposition is off-axis. Local transport analysis illustrated that both electron and ion thermal diffusivities are decreased during the LHW phase, and the electron internal transport barriers (eITBs) are formed while been accompanied by the ion internal transport barriers (iITBs) during LHW phase. Ions are heated by electron-ion collision in the region of the barriers although the ohmic power and the LHW power were absorbed by the electrons. Both electron temperature and ion temperature are increased during the LHW phase, and in the confinement region, the electron-to-ion temperature ratio, Te/Ti varies from 2.0 ~ 2.5 during OH phase to 1.3 ~ 1.6 during LHW injected into the plasma, which shows that electron confinement is not degraded by the electron–ion collisions meanwhile ions are also confined. The energy confinement is increased from 13 ms to 25 ms due to the formation of electron and ion internal transport barries after the LHW is injected into the plasma. LHW driven current and bootstrap current contribute to 60% of the total current.

Type
Papers
Information
Journal of Plasma Physics , Volume 76 , Issue 2 , April 2010 , pp. 229 - 237
Copyright
Copyright © Cambridge University Press 2009

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References

[1]Buratti, P., Barbato, E., Bracco, G., Cirant, S., Crisanti, F., Granucci, G., Tuccillo, A. A., Zanza, V., Zerbini, M., Acitelli, L. et al. 1999 High core electron confinement regimes in FTU plasmas with low- or reversed-magnetic shear and high power density electron-cyclotron-resonance heating. Phys Rev. Lett 82, 560–563.CrossRefGoogle Scholar
[2]Hogeweij, G. M. D., Baranov, Y., Challis, C. D., Conway, G. D., Crisanti, F., De Baar, M. R., Hawkes, N., Imbeaux, F., Litaudon, X., Mailloux, J. et al. 2001 Electron heated internal transport barriers in JET. In: 28th EPS Conference on Contr. Fusion and Plasma Phys. Funchal, 18–22 June 2001 ECA, Vol. 25A, pp. 485–488.Google Scholar
[3]Angelini, B., Annibaldi, S. V., Apicella, M. L., Apruzzese, G., Barbato, E., Bertocchi, A., Bombarda, F., Bourdelle, C., Bruschi, A., Buratti, P. et al. 2005 Overview of the FTU results. Nucl. Fusion 45, S227–S238.CrossRefGoogle Scholar
[4]Fujita, T., Fukuda, T., Sakamoto, Y., Ide, S., Suzuki, T., Takenaga, H., Ida, K., Idei, H., Shimozuma, T., Fujisawa, A. et al. 2004 Formation conditions for electron internal transport barriers in JT-60U plasmas. Plasma Phys. Control. Fusion 46, A35–A43.CrossRefGoogle Scholar
[5]Frassinetti, L., Alfier, A., Pasqualotto, R., Bonomo, F. and Innocente, P. 2008 Heat diffusivity model and temperature simulations in RFX-mod. Nucl. Fusion 48, 045007.CrossRefGoogle Scholar
[6]Suzuki, T., Ide, S., Oikawa, T., Fujita, T., Ishikawa, M., Seki, M., Matsunaga, G., Hatae, T., Naito, O., Hamamatsu, K. et al. 2008 Off-axis current drive and real-time control of current profile in JT-60U. Nucl. Fusion 48, 045002CrossRefGoogle Scholar
[7]Ide, S., Naito, O., Oikawa, T., Fujita, T., Kondoh, T., Seki, M., Ushigusa, K. and JT-60 Team 2000 LHCD current profile control experiments towards steady state improved confinement on JT-60U. Nuclear Fusion 40, 445–451.CrossRefGoogle Scholar
[8]Pamela, J., Solano, E. R., Adams, J. M., Agarici, G., Agarici, M., Akhter, H., Albanese, R., Alberti, S., Allfrey, S., Alper, B. et al. 2003 Overview of JET results. Nucl. Fusion 43, 1540–1554.CrossRefGoogle Scholar
[9]Tuccillo, A. A., Barbato, E., Bae, Y. S., Becoulet, A., Bernabei, S., Bibet, P., Calabrò, G., Cardinali, A., Castaldo, C., Cesario, R. et al. 2005 Progress in LHCD: a tool for advanced regimes on ITER. Plasma Phys. Control. Fusion 47, B363–B377.CrossRefGoogle Scholar
[10]Kuang, G., Liu, Y., Shan, J., Xu, W., Zhang, X., Liu, D., Liu, F., Zhu, Y., Zhang, C., Zheng, G. et al. 1999 Lower hybrid current drive experiments and improved performance on the HT-7 superconducting tokamak. Nucl. Fusion 39, 1769–1774.CrossRefGoogle Scholar
[11]Gao, X., Xu, Q., Li, J. G., Shan, J. F., Hu, L. Q., Zhao, J. Y. and the HT-7 Team 2008 Study of confinement and LHCD efficiency on the HT-7 tokamak. Plasma Phys. Control. Fusion 50, 035006.CrossRefGoogle Scholar
[12]Ding, B., Kuang, G., Liu, Y., Shan, J., Shen, W., Yu, J., Liu, S., Shi, Y., Jie, Y., Wan, B. et al. 2002 Improved confinement through internal transport barrier formation with lower hybrid current drive in the Hefei Tokamak-7. Phys. Plasma 9, 4996–5000.CrossRefGoogle Scholar
[13]Ignat, D. W., Valeo, E. J. and Jardin, S. C. 1994 Dynamic modelling of lower hybrid current drive. Nucl. Fusion 34, 837–852.CrossRefGoogle Scholar
[14]Wesson, J. 1997 Tokamaks. Clarendon: Oxford, pp. 663.Google Scholar