volume | PIER Journals

Abstract

The launching of high-frequency electromagnetic waves into fusion plasmas is an effective method for plasma heating and noninductive current drive. In addition, the reflection of electromagnetic waves on the plasma cutoffs is utilized in electron density diagnostic measurements. The scope of this article is to comment on the standard approximations made in the simulation of electron-cyclotron wave propagation and absorption in tokamak plasmas, in connection to the established modeling tools and the underlying physics, as well as to illustrate the limits of their validity, especially regarding the applicability to ITER-related studies and beyond. The identification of possible gaps in the current state-of-the-art and the implication of new requirements for theory and modeling are also discussed.

1. Erckmann, V. and U. Gasparino, "Electron cyclotron resonance heating and current drive in toroidal fusion plasmas," Plasma Phys. Control. Fusion, Vol. 36, No. 12, 1869-1962, 1994.
doi:10.1088/0741-3335/36/12/001

2. Prater, R., "Heating and current drive by electron-cyclotron waves," Phys. Plasmas, Vol. 11, No. 5, 2349-2376, 2004.
doi:10.1063/1.1690762

3. Stix, T. H., Waves in Plasmas, Springer-Verlag, New York, 1992.

4. La Haye, R. J., "Neoclassical tearing modes and their control," Phys. Plasmas, Vol. 13, No. 6, Art. 055501, 2006.

5. Wesson, J., Tokamaks, Oxford University Press, New York, 2004.

6. Swanson, D. G., Plasma Waves, Taylor-Francis, New York, 2003.

7. Pinches, S. D., The HAGIS Self-consistent Nonlinear Wave-particle Interaction Models, UKAEA Fusion, Culham, 1998.

8. Tsironis, C. and L. Vlahos, "Effect of nonlinear wave-particle interaction on electron-cyclotron absorption," Plasma Phys. Control. Fusion, Vol. 48, No. 9, 1297-1310, 2006.
doi:10.1088/0741-3335/48/9/003

9. Kline, M. and I. W. Kay, Electromagnetic Theory and Geometrical Optics, Interscience, New York, 1965.

10. Friedland, L. and I. B. Bernstein, "General geometric optics formalism in plasmas," IEEE Trans. Plasma Sci., Vol. 8, No. 2, 90-95, 1980.
doi:10.1109/TPS.1980.4317277

11. Kravtsov, Y. I. and Y. A. Orlov, Geometrical Optics of Inhomogeneous Media, Springer-Verlag, Berlin, 1990.

12. Mazzucato, E., "Propagation of Gaussian beam in inhomogeneous plasma," Phys. Fluids B, Vol. 1, No. 9, 1855-1860, 1989.
doi:10.1063/1.858917

13. Nowak, S. and A. Orefice, "Three-dimensional propagation and absorption of high frequency Gaussian beams in magnetoactive plasmas," Phys. Plasmas, Vol. 1, No. 5, 1242-1250, 1994.
doi:10.1063/1.870721

14. Pereverzev, G. V., "Beam tracing in inhomogeneous anisotropic plasma," Phys. Plasmas, Vol. 5, No. 10, 3529-3541, 1998.
doi:10.1063/1.873070

15. Taflove, A., Computational Electrodynamics: The Finite-difference Tiem-domain Method, Artech House, London, 2000.

16. Tsironis, C., T. Samaras, and L. Vlahos, "Scattered-field FDTD algorithm for hot anisotropic plasma with application to electron-cyclotron heating," IEEE Trans. Ant. Prop., Vol. 56, No. 9, 2988-2994, 2008.
doi:10.1109/TAP.2008.928774

17. Koehn, A., A. Cappa, E. Holzhauer, F. Castejon, A. Fernandez, and U. Stroth, "Full-wave calculation of the O-X-B mode conversion of Gaussian beams in a cylindrical plasma," Plasma Phys. Control. Fusion, Vol. 50, No. 8, Art. 085018, 2008.

18. Kamendje, R., S. V. Kasilov, W. Kernbichler, and M. F. Heyn, "Kinetic modeling of nonlinear electron cyclotron resonance heating," Phys. Plasmas, Vol. 10, No. 1, 75-97, 2003.
doi:10.1063/1.1525796

19. Isliker, H., I. Chatziantonaki, C. Tsironis, and L. Vlahos, "Electron-cyclotron wave propagation, absorption and current drive in the presence of neoclassical tearing modes," Plasma Phys. Control. Fusion, Vol. 54, No. 9, Art. 095005, 2012.

20. Ayten, B. and E. Westerhof, "Consequences of plasma rotation for neoclassical tearing mode suppression by electron cyclotron current drive," Phys. Plasmas, Vol. 18, No. 9, Art. 092506, 2012.

21. Westerhof, E., Implementation of TORAY at JET, Rijnhuizen Report 89-183, Eindhoven, 1989.

22. Poli, E., A. G. Peeters, and G. V. Pereverzev, "TORBEAM, a beam tracing code for electron-cyclotron waves in tokamak plasmas," Comput. Phys. Commun., Vol. 136, No. 1, 90-104, 2001.
doi:10.1016/S0010-4655(01)00146-1

23. Farina, D., "Quasi-optical propagation of an EC Gaussian beam, absorption and current drive in tokamaks," AIP Conf. Proc., Vol. 871, 77-86, 2006.

24. Lloyd, B., "Overview of ECRH experimental results," Plasma Phys. Control. Fusion, Vol. 40, No. 4, A119-A138, 1998.
doi:10.1088/0741-3335/40/8A/010

25. Tsironis, C., E. Poli, and G. V. Pereverzev, "Beam tracing description of non-Gaussian wave beams," Phys. Plasmas, Vol. 13, Art. 113304, 2006.

26. Goldston, R. J. and P. H. Rutherford, Introduction to Plasma Physics, IoP Publishing, Boston, 1995.

27. Maj, O., G. V. Pereverzev, and E. Poli, "Validation of the paraxial beam-tracing method in critical cases," Phys. Plasmas, Vol. 16, Art. 062105, 2009.

28. Tsironis, C., A. G. Peeters, H. Isliker, D. Strintzi, I. Chatziantonaki, and L. Vlahos, "EC wave scattering by edge density fluctuations in ITER," Phys. Plasmas, Vol. 16, Art. 112510, 2009.

29. Brunner, S. and J. Vaclavik, "Dielectric tensor operator of hot plasmas in toroidal axisymmetric systems," Phys. Fluids B, Vol. 5, No. 6, 1695-1705, 1992.
doi:10.1063/1.860804

30. Kominis, Y., A. K. Ram, and K. Hizanidis, "Distribution functions of wave-particle interactions in plasmas," Phys. Rev. Lett., Vol. 104, No. 8, 23-26, 2010.

31. Westerhof, E., "Propagation through an EC resonance layer," Plasma Phys. Control. Fusion, Vol. 39, No. 6, 1015-1029, 1997.

32. Ram, A. K. and J. Decker, "Relativistic effects in electron cyclotron resonance heating and current drive," Proc. 35th EPS Conference, Art. 1-097, 2008.

33. Farina, D., "Relativistic dispersion relation of electron cyclotron waves," Fus. Sci. Tech., Vol. 53, No. 1, 130-138, 2008.

34. Poli, E., E. Fable, G. Tardini, H. Zohm, D. Farina, L. Figini, N. B. Marushchenko, and L. Porte, "Assessment of ECCD-assisted operation in DEMO," Proc. EC-17, Art. 01005, 2012.

35. Sirenko, K., V. Pazynin, Y. K. Sirenko, and H. Bagci, "An FFT-accelerated FDTD scheme with exact absorbing conditions for characterizing axially symmetric resonant structures," Progress In Electromagnetics Research, Vol. 111, 331-364, 2011.

Prof. Christos Tsironis