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Edge stability and transport control with resonant magnetic perturbations in collisionless tokamak plasmas

Nature Physics volume 2, pages 419–423 (2006)Cite this article

Abstract

A critical issue for fusion-plasma research is the erosion of the first wall of the experimental device due to impulsive heating from repetitive edge magneto-hydrodynamic instabilities known as 'edge-localized modes' (ELMs). Here, we show that the addition of small resonant magnetic field perturbations completely eliminates ELMs while maintaining a steady-state high-confinement (H-mode) plasma. These perturbations induce a chaotic behaviour in the magnetic field lines, which reduces the edge pressure gradient below the ELM instability threshold. The pressure gradient reduction results from a reduction in the particle content of the plasma, rather than an increase in the electron thermal transport. This is inconsistent with the predictions of stochastic electron heat transport theory. These results provide a first experimental test of stochastic transport theory in a highly rotating, hot, collisionless plasma and demonstrate a promising solution to the critical issue of controlling edge instabilities in fusion-plasma devices.

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Figure 1: ELM response to an applied magnetic perturbation.
Figure 2: Changes in the ELM response with increasing magnetic perturbation levels.
Figure 3: The value of the safety factor at the 95% magnetic flux surface (q95) influences the ELM response to the RMP.
Figure 4: Changes in the edge-plasma profiles with various magnetic perturbation levels.
Figure 5: ELM stability diagram.
Figure 6: Contour plot of the magnetic perturbation spectrum.

References

  1. Callen, J. D., Carreras, B. A. & Stambaugh, R. D. Stability and transport processes in tokamak plasmas. Phys. Today 45, 34–42 (1992).

    Article  ADS  Google Scholar 

  2. Wesson, J. Tokamaks 3rd edn, Ch. 13, 711–717 (Oxford Univ. Press, Oxford, 2004).

    MATH  Google Scholar 

  3. Snyder, P. B. et al. Edge localized modes and the pedestal: A model based on coupled peeling-ballooning modes. Phys. Plasmas 9, 2037–2043 (2002).

    Article  ADS  Google Scholar 

  4. ITER Website <http://www.iter.org>.

  5. Loarte, A. et al. Characteristics of type I ELM energy and particle losses in existing devices and their extrapolation to ITER. Plasma Phys. Control. Fusion 45, 1549–1569 (2003).

    Article  ADS  Google Scholar 

  6. Loarte, A. et al. ELM energy and particle losses and their extrapolation to burning plasma experiments. J. Nucl. Mater. 313–316, 962–966 (2003).

    Article  ADS  Google Scholar 

  7. Evans, T. E. et al. Experiments to test an intra-island scoop limiter on TEXT. J. Nucl. Mater. 145–146, 812–815 (1987).

    Article  ADS  Google Scholar 

  8. Ghendrih, Ph., Grosman, A. & Caps, H. Theoretical and experimental investigations of stochastic boundaries in tokamaks. Plasma Phys. Control. Fusion 38, 1653–1724 (1996).

    Article  ADS  Google Scholar 

  9. Jakubowski, M. W et al. Change of the magnetic-field topology by an ergodic divertor and the effect on the plasma structure and transport. Phys. Rev. Lett. 96, 035004 (2006).

    Article  ADS  Google Scholar 

  10. Rechester, A. B. & Rosenbluth, M. N. Electron heat transport in a tokamak with destroyed magnetic surfaces. Phys. Rev. Lett. 40, 38–41 (1978).

    Article  ADS  Google Scholar 

  11. Mori, M. et al. in Proc. Int. Conf. on Control. Fusion and Plasma Phys. (Würzburg, Austria) Vol. 2, 567–573 (1992).

    Google Scholar 

  12. Fielding, S. J. et al. in Proc. 28th EPS Conference on Contr. Fusion and Plasma Phys., (Funchal, Portugal, June 2001) 1825–1828 (ECA, Vol. 25A, 2001).

  13. Evans, T. E. et al. Suppression of large edge-localized modes in high-confinement DIII-D plasmas with a stochastic magnetic boundary. Phys. Rev. Lett. 92, 235003 (2004).

    Article  ADS  Google Scholar 

  14. Moyer, R. A. et al. Edge localized mode control with an edge resonant magnetic perturbation. Phys. Plasmas 12, 056119 (2005).

    Article  ADS  Google Scholar 

  15. Evans, T. E. et al. Suppression of large edge localized modes with edge resonant magnetic fields in high confinement DIII-D plasmas. Nucl. Fusion 45, 595–607 (2005).

    Article  ADS  Google Scholar 

  16. Evans, T. E. et al. Suppression of large edge localized modes in high confinement DIII-D plasmas with a stochastic magnetic boundary. J. Nucl. Mater. 337–339, 691–696 (2005).

    Article  ADS  Google Scholar 

  17. Burrell, K. H. et al. ELM suppression in low edge collisionality H-mode discharges using n=3 magnetic perturbations. Plasma Phys. Control. Fusion 47, B37–B52 (2005).

    Article  Google Scholar 

  18. D'haeseleer, W. D., Hitchon, W. N. G., Callen, J. D. & Shohet, J. L. Flux Coordinates and Magnetic Field Structure (Springer, Berlin, 1991).

    Book  Google Scholar 

  19. Burrell, K. H. et al. Advances in understanding quiescent H-mode plasmas in DIII-D. Phys. Plasmas 12, 056121 (2005).

    Article  ADS  Google Scholar 

  20. Wilson, H. R., Snyder, P. B., Huysmans, G. T. A. & Miller, R. L. Numerical studies of edge localized instabilities in tokamaks. Phys. Plasmas 9, 1277–1286 (2002).

    Article  ADS  Google Scholar 

  21. Evans, T. E. et al. The physics of edge resonant magnetic perturbation in hot tokamak plasmas. Phys. Plasmas 13 (May) (2006) in the press.

  22. Stangeby, P. The Plasma Boundary of Magnetic Fusion Devices 1st edn, Ch. 10, 417 (Institute of Physics Publishing, London, 2000).

    Book  Google Scholar 

  23. Porter, G. D. et al. Characterization of the separatrix plasma parameters in DIII-D. Phys. Plasmas 5, 1410–1422 (1998).

    Article  ADS  Google Scholar 

  24. Fitzpatrick, R. Bifurcated states of a rotating tokamak plasma in the presence of a static error-field. Phys. Plasmas 5, 3325–3341 (1998).

    Article  ADS  Google Scholar 

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Acknowledgements

We would like to thank R. J. La Haye for pointing out that magnetic shielding due to edge-plasma rotation may be a significant effect in these experiments. This work was supported by the US Department of Energy under DE-FC02-04ER54698,W-7405-ENG-48, and DE-FG02-04ER54758.

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Authors and Affiliations

  1. General Atomics, San Diego, California, 92186-5608, USA

    Todd E. Evans, Keith H. Burrell, Anthony W. Leonard, Thomas H. Osborne, Michael J. Schaffer, Philip B. Snyder & William P. West

  2. University of California, San Diego, California, 92093-0417, USA

    Richard A. Moyer & Ilon Joseph

  3. Lawrence Livermore National Laboratory, Livermore, California, 94551-0808, USA

    Max E. Fenstermacher & Gary D. Porter

  4. Association EURATOM-CEA, CEA Cadarache, F-13108, St. Paul Lez Durance, France

    Paul R. Thomas

  5. Sandia National Laboratories, Albuquerque, New Mexico, 87185, USA

    Jonathan G. Watkins

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  1. Todd E. Evans
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Correspondence to Todd E. Evans.

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Evans, T., Moyer, R., Burrell, K. et al. Edge stability and transport control with resonant magnetic perturbations in collisionless tokamak plasmas. Nature Phys 2, 419–423 (2006). https://doi.org/10.1038/nphys312

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