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Plasma-Wall Interactions in Tandem Mirror Machines

  • Steven L. Allen
  • The TMX-U/MFTF-B Experimental Teams

Abstract

Plasma-surface interactions can play an important role in the present generation of tandem mirror machines, such as the Tandem Mirror Experiment-Upgrade (TMX-U),1 Phaedrus,2 Gamma-10,3 and TARA4, which are currently operational; and AMBAL,5 which will soon be fully operational. The importance of plasma-surface interactions may be even more pronounced in larger, longer-pulse tandem mirrors such as the Mirror Fusion Test Facility (MFTF-B),6,7 which will be used to investigate plasmas at reactor-like conditions. However, current experiments and models of future experiments indicate that plasma-surface interactions can be minimized in tandem mirror machines. This is in part due to the inherent open field lines of the confinement configuration. In particular, plasma-surface interactions can be controlled at radial surfaces by controlling the axial confinement of the edge plasma.

Keywords

Central Cell Lawrence Livermore National Laboratory Edge Plasma Neutral Beam Neutral Beam Injection 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    T. C. Simonen, D. E. Baldwin, S. L. Allen, “TMX Tandem Mirror Experiments and Thermal-Barrier Theoretical Studies,” in Proc. 9th Intern. Conf. Plasma Physics and Controlled Nuclear Fusion Research, held in Baltimore, MD, 1982 (IAEA, Vienna, 1983), Vol. 1, p. 519.Google Scholar
  2. 2.
    N. Hershkowitz, R. A. Breun, D. Brouchous, “Recent Experiments in the Phaedrus Tandem Mirror,” in Proc. 9th Intern. Conf. Plasma Physics and Controlled Nuclear Fusion Research, Baltimore, MD (1982), IAEA, Vienna, 1983, vol. 1, p. 553.Google Scholar
  3. 3.
    M. Inutake, K. Ishii, A. Itakura, “Studies of Improvement of Plasma Confinement in Axisymmetrized Tandem Mirror,” in Proc. 9th Intern. Conf. Plasma Physics and Controlled Nuclear Fusion Research, Baltimore, MD, (1982), IAEA, Vienna, 1983, vol. 1, p. 545.Google Scholar
  4. 4.
    J. Kesner, R. S. Post, B. D. McVey, and D. K. Smith, “A Tandem Mirror with Axisymmetric Central-Cell Ion Confinement,” Nuc. Fus. 22 549–560 (1982a).CrossRefGoogle Scholar
  5. 5.
    G. I. Dimov and G. V. Roslyakov, A Trap With Ambipolar Plugs, (Institute of Nuclear Physics, Novosibirsk, USSR, Preprint 80–1520), published by Lawrence Livermore National Laboratory, Livermore, CA, UCRL-TRANS-11670 (1981).Google Scholar
  6. 6.
    D. E. Baldwin, B. G. Logan, T. C. Simonen, Physics Basis for MFTF-B, Lawrence Livermore National Laboratory, Livermore, CA, UCID-18496 (1980).Google Scholar
  7. 7.
    K. I. Thomassen, V. N. Karpenko, An Axicell Design for the End Plugs of MFTF-B, Lawrence Livermore National Laboratory, Livermore, CA, UCID-19318 (1982).CrossRefGoogle Scholar
  8. 8.
    R. P. Drake, Nuclear Technology/Fusion 3 405 (1983).Google Scholar
  9. 9.
    W. L. Hsu, “Review of Plasma Wall Interaction Experiments on TMX and TMX-U,” in Proc. 6th Intl. Conf. on Plasma-Surface Interactions in Controlled Fusion Devices, Nagoya, Japan (1984). To be published in the J. of Nucl. Instr. and Mater.Google Scholar
  10. 10.
    S. L. Allen and the TMX-U/MFTF-B Experimental Team, “Plasma-Surface Interactions in Large Tandem Mirror Devices—MFTF-B” in Proc. 6th International Conference on Plasma-Surface Interactions in Controlled Fusion Devices, Nagoya, Japan (1984). To be published in the J. of Nucl. Instr. and Mater.Google Scholar
  11. 11.
    K. I. Thomassen, B. G. Logan, J. N. Doggett, and F. H. Coensgen, “A DT-Burning Upgrade to MFTF-B”, in Proc. 6th Intl. Conf. on Plasma-Surface Interactions in Controlled Fusion Devices, Nagoya, Japan (1984).Google Scholar
  12. 12.
    B. G. Logan, MARS Final Report, Lawrence Livermore National Laboratory, Livermore, CA, UCRL-53480 (1984).Google Scholar
  13. 13.
    C. C. Damm, J. H. Foote, A. H. Futch, A. L. Gardner, and R. F. Post, Phys. Rev. Lett. 13 464 (1964).ADSCrossRefGoogle Scholar
  14. 14.
    R. W. Moir and R. F. Post, Nucl. Fusion 9 253 (1969).CrossRefGoogle Scholar
  15. 15.
    R. F. Post, in Proc. Intl. Conf. Plasma Confined in Open-Ended Geometry (Gatlinburg, TN, 1967), p. 309; also published as Oak Ridge National Laboratory, Oak Ridge, TN, CONF-671127.Google Scholar
  16. 16.
    F. H. Coengsen, W. F. Cummins, B. G. Logan, A. W. Molvik, W. E. Nexsen, T. C. Simonen, B. W. Stallard, and W. C. Turner, in Proc. 7th Eur. Conf. Cont. Fusion Plasma Phys., Vol. II, p. 167 (1975).Google Scholar
  17. 17.
    R. W. Moir, Standard Mirror Fusion Reactor Design Study, Lawrence Livermore National Laboratory, Livermore, CA, UCID-17644 (1978).Google Scholar
  18. 18.
    D. L. Correll, Nuc. Fus. 22 223 (1982).CrossRefGoogle Scholar
  19. 19.
    T. A. Casper and G. R. Smith, Phys. Rev. Lett. 48 1015 (1982).ADSCrossRefGoogle Scholar
  20. 20.
    D. E. Baldwin and B. G. Logan, Phys. Rev. Lett. 43 1318 (1979).ADSCrossRefGoogle Scholar
  21. 21.
    T. C. Simonen, Phys. Rev. Lett. 50 1668 (1983).ADSCrossRefGoogle Scholar
  22. 22.
    D. P. Grubb, S. L. Allen, J. D. Barter, “Thermal Barrier Production and Identification in a Tandem Mirror,” submitted to Phys. Rev. Lett.; Lawrence Livermore National Laboratory, Livermore, CA, UCRL-90536.Google Scholar
  23. 23.
    T. C. Simonen, S. L. Allen, T. A. Casper, “TMX-U Experimental Results,” in Proc. of Course/Workshop on Mirror-Based Approaches to Magnetic Fusion, Varenna, Italy, Sept. 7–17, 1983; published by Lawrence Livermore National Laboratory, Livermore, CA, UCRL-89286 (1983).Google Scholar
  24. 24.
    T. A. Casper, L. V. Berzins, R. F. Ellis, R. A. James, and C. Lasnier, “Microstability of TMX-U During Initial Thermal Barrier Operation,” in Proc. of Intl. Conf. on Plasma Physics, Lausanne, Switzerland (1984); Lawrence Livermore National Laboratory, Livermore, CA, UCRL-90451.Google Scholar
  25. 25.
    W. C. Turner, W. E. Nexsen, S. L. Allen, “Gas Pressure in the End Plug Regions of the TMX-U Thermal Barrier Experiment,” submitted to the J. Vac. Sci. Technol. (1983); Lawrence Livermore National Laboratory, Livermore, CA, UCRL-89938.Google Scholar
  26. 26.
    A. A. Marin, S. P. Auerbach, R. H. Cohen, J. M. Gilmore, L. D. Pearlstein, and M. E. Rensink, Nuc. Fus.23 703 (1983). See also D. E. Baldwin and B. G. Logan (Eds.), Physics Basis for an Axicell Design for the End Plugs of MFTF-B, Lawrence Livermore National Laboratory, Livermore, CA, UCID-19359 (1982).CrossRefGoogle Scholar
  27. 27.
    L. D. Pearlstein, D. E. Baldwin, R. H. Cohen, T. K. Fowler, and B. G. Logan, “Stabilization of Tandem-Mirror Trapped-Particle Modes by Incomplete Cancellation of Trapped-Particle Drifts,” presented at 1982 Sherwood Meeeting, Annual Controlled Fusion Theory Conference, Santa Fe, NM, April 25–28, 1982.Google Scholar
  28. 28.
    E. B. Hooper, Jr., D. E. Baldwin, T. K. Fowler, R. J. Kane, and W. C. Turner, “Radial Transport Reduction in Tandem Mirrors Using End Wall Boundary Conditions,” submitted to Physics of Fluids (1984); Lawrence Livermore National Laboratory, Livermore, CA, UCRL-90639.Google Scholar
  29. 29.
    D. L. Correll, J. A. Byers, T. A. Casper, Throttle Coil Operation of TMX-U, Lawrence Livermore National Laboratory, Livermore, CA, UCID-19650 (1983).CrossRefGoogle Scholar
  30. 30.
    Y-J. Chen, D. E. Baldwin, and T. Q. Hua, “Analytic Model and Simulations of RF Drift Pumping of Thermal Barriers,” Bull. Amer. Phys. Soc. 28 1195 (1983).Google Scholar
  31. 31.
    B. W. Stallard, F. H. Coensgen, W. F. Cummins, “Plasma Wall Charge Exchange Interactions in the 2XIIB Magnetic Mirror Experiment,” in Proc. International Symposium on Plasma Wall Interaction, Jülich, Federal Republic of Germany, Pergamon Press, p. 63. (1976)Google Scholar
  32. 32.
    D. L. Correll, J. F. Clauser, F. H. Coensgen, Nuc. Fus. 20 655 (1980).ADSCrossRefGoogle Scholar
  33. 33.
    F. Najmabadi, and R. W. Conn, “Radius Control System for Tandem Mirrors,” submitted to Nuclear Technology/Fusion (1984).Google Scholar
  34. 34.
    J. R. Farron, R. A. Breun, S. N. Golovato, “Scaling of RF Sustained Tandem Mirror Parameters With Central Cell Heating Power Including a Central Cell Stand-Alone Mode,” Bull. Amer. Phys. Soc. 27 958 (1982).Google Scholar
  35. 35.
    D. Garner, private communications, May 1984.Google Scholar
  36. 36.
    S. L. Allen, C. A. Clower, and W. C. Turner, “The Influence of Vacuum and Wall Conditioning on Plasma Startup in TMX-U,” Bull. Am. Phys. Soc. 28 1114 (1983).Google Scholar
  37. 37.
    H. F. Dylla, in Proc. of the 29th National Symposium (American Vacuum Society, Baltimore, MP).Google Scholar
  38. 38.
    S. L. Allen, C. Clower, R. P. Drake, E. B. Hooper, Jr., A. L. Hunt, R. Munger, R. J. Bastasz, W. Bauer, and W. L. Hsu, “Initial Wall Conditioning for the TMX-U Fusion Experiment, J. Vac. Sci. Technol. A 1(2) 916 (1983).ADSCrossRefGoogle Scholar
  39. 39.
    J. E. Osher, G. D. Porter, L. E. Valby, Glow Discharge Cleaning Tests of MFTF-B Cryopanel Components, Lawrence Livermore National Laboratory, Livermore, CA, Quarterly Jan.-May, 1981, UCRL-50051–81–1 (1981).Google Scholar
  40. 40.
    W. L. Pickles, in Proc. of the 29th National Vacuum Syposium (American Vacuum Society, Baltimore, MD, 1982).Google Scholar
  41. 41.
    W. Bauer, Bull. Am. Phys. Soc. 27 1137 (1982).Google Scholar
  42. 42.
    O. T. Strand, H. W. Moos, and S. L. Allen, “Experimental Evidence for Outward Radial Transport of Impurities from the Central Cell of TMX,” Nuc. Fus. 23 (12) (1983).Google Scholar
  43. 43.
    G. E. Gryczkowski, Neutral Gas Blanket Theory as Applied to the Reference Theta Pinch Reactor, Ph.D. Thesis, Univ. of Michigan, Dept. of Nuclear Engineering (1979).Google Scholar
  44. 44.
    R. P. Drake and H. W. Moos, Nuc. Fus. 19 407 (1979).ADSCrossRefGoogle Scholar
  45. 45.
    J. E. Osher, D. P. Grubb, and P. Poulsen, “Impurity Accumulation in a Tandem Mirror,” Bull. Am. Phys. Soc. 1119 (1983).Google Scholar
  46. 46.
    L. S. Hall, Nuc. Fus. 17 681 (1977).ADSCrossRefGoogle Scholar
  47. 47.
    B. W. Stallard, “ECRH in Tandem Mirror Machines,” in Proc. of IEEE Minicourse on RF Heating and Current Drive, San Diego, CA, 1983; Lawrence Livermore National Laboratory, Livermore, CA, UCRL-89276.Google Scholar
  48. 48.
    S. L. Allen, T. L. Yu, and T. J. Nash, “Impurity Characteristics of TMX-U,” Lawrence Livermore National Laboratory, Livermore, CA, UCID-20026 (1984).CrossRefGoogle Scholar
  49. 49.
    P. Coakley, N. Hershkowitz, and G. D. Porter, “End-Wall Plasma Characteristics in the Tandem Mirror Experiments,” Nuc. Fus. 22 1321 (1982).CrossRefGoogle Scholar
  50. 50.
    G. D. Porter, “Effect of Gas Recycling and Secondary Emission on the Axial Flow in an Open-Ended Device,” Nuc. Fus. 22 1279 (1982).CrossRefGoogle Scholar
  51. 51.
    K. Muraoka, M. Maeda, T. Okada, in Proc. of 6th Intl. Conf. on Plasma Surf. Int. in Cont. Fus. Devices 1984.Google Scholar

Copyright information

© Plenum Press, New York 1986

Authors and Affiliations

  • Steven L. Allen
    • 1
  • The TMX-U/MFTF-B Experimental Teams
  1. 1.Lawrence Livermore National LaboratoryUniversity of CaliforniaLivermoreUSA

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