Hostname: page-component-8448b6f56d-sxzjt Total loading time: 0 Render date: 2024-04-19T22:02:19.563Z Has data issue: false hasContentIssue false
  • English
  • Français

Compact toroid formation, dynamics and lifetime in collisional plasmas generated at high fill pressures

Published online by Cambridge University Press:  13 March 2009

J. C. Dooling ,
T. M. York ,
M. Niimura ,
F. Aghamir ,
F. B. Mead  and
D. R. Shieh
J. C. Dooling
Affiliation:
The Pennsylvania State University, University Park, Pennsylvania, U.S.A.
T. M. York
Affiliation:
The Pennsylvania State University, University Park, Pennsylvania, U.S.A.
M. Niimura
Affiliation:
The Pennsylvania State University, University Park, Pennsylvania, U.S.A.
F. Aghamir
Affiliation:
The Pennsylvania State University, University Park, Pennsylvania, U.S.A.
F. B. Mead
Affiliation:
The Pennsylvania State University, University Park, Pennsylvania, U.S.A.
D. R. Shieh
Affiliation:
The Pennsylvania State University, University Park, Pennsylvania, U.S.A.
Get access Rights & Permissions [Opens in a new window]

Abstract

A 0·50 m long compact-toroid transport experiment (CTTX) has been studied with a number of diagnostics, including Thomson scattering, to determine local plasma properties and gradients indicative of transport processes. The CTTX bias and main field strengths were –0·09 and 0·35 T. Compact toroid formation and lifetime were studied at static fill pressures of 20, 100 and 150 mTorr deuterium, between 3 and 30μs after firing of the main bank. Thomson-scattering diagnosis was carried out using a Q-switched Nd: glass laser operated at both fundamental (1053 nm) and second-harmonic wavelengths (527 nm). For each pressure, scattering tests were conducted at radii r of 0·1, 1·0, 1·85 and 2·60 cm and axial positions z of 6·7, 13·0 and 19·0 cm (1054 nm); supplementary data were obtained at r = 0·1, 1·35 and 2·10 cm at z = 6·7 cm (527 nm). Electron densities and temperatures were in the ranges 1021–1022 m-3 and 2–20 eV. Thomson-scattering results are compared with diamagnetic loop, inter-ferometry, luminosity and piezoelectric pressure-probe data. Axial behaviour of the formation CT plasma varies significantly with initial fill pressure: continuous axial contraction occurs at ISOmTorr; whereas the 20 mTorr plasma appears first to contract then expand. Particle loss times are found to decrease from 70 μs at 20 mTorr to 24 μs at 100 mTorr and 12 μs at 150 mTorr. Energy decay times are 6, 7 and 5 μs for 20, 100 and 150 mTorr respectively. Flux-decay times are approximately 20 μs for 20 mTorr, 12 μs for 100 mTorr and 20 μs for 150 mTorr fill pressure. These values are two to four times longer than would be expected from theory using classical transport. In order to explain the sustained magnetic flux, the role of electric fields within the compact toroid is considered.

Type
Research Article
Information
Journal of Plasma Physics , Volume 43 , Issue 3 , June 1990 , pp. 419 - 449
Copyright
Copyright © Cambridge University Press 1990

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

REFERENCES

Armstrong, W. T., Chrien, R. E., McKenna, K. F., Rej, D. J., Shekwood, E. G., Siemon, R. E. & Tuszewski, M. 1984 Proceedings of the 6th U.S. Symposium on Compact Toroid Research, ed. M. Yamada and R. Ellis, Jr., Princeton University, p. 218. Princeton, New Jersey, 20–23 February 1984.Google Scholar
Armstrong, W. T., Linford, R. K., Lipson, J., Platts, D. A. & Sherwood, E. G. 1981 Phys. Fluids, 24, 2068.CrossRefGoogle Scholar
Brunhns, H., Bhendel, R., Raupp, G., Schulte, U. & Steiger, J. 1987 Proceedings of the 8th U.S. Compact Toroid Symposium, ed. A. W. DeSilva and G. C. Goldenbaum, University of Maryland, p. 23. College Park, Maryland, 4–5 June 1987.Google Scholar
Chrien, R. E., Barnes, G. A., Hugrass, W. N., Ling, K. M., Okada, S., Rej, D. J. & Siemon, R. E. 1986 Bull. Am. Phys. Soc. 31, 1487.Google Scholar
Dooling, J. C. & York, T. M. 1987 Proceedings of the 8th U.S. Symposium on Compact Toroid Research, ed. A. W. DeSilva and G. C. Goldenbaum, University of Maryland, p. 126. College Park, Maryland, 4–5 June 1987.Google Scholar
Dooling, J. C. & York, T. M. 1988 Rev. Sci. Instrum. 59, 1473.CrossRefGoogle Scholar
Eberhagen, A. & Grossmann, W. 1971 Z. Phys. 248, 130.CrossRefGoogle Scholar
Freidberg, J. P. & Pearlstein, L. D. 1978 Phys. Fluids, 21, 1207.Google Scholar
Heikkinen, J. A., Karttunen, S. J. & Salomaa, R. R. E. 1988 Nucl. Fusion, 28, 1845.Google Scholar
Hoffman, A. L., Milroy, R. D. & Steinhauer, L. C. 1982 Appl. Phys. Lett. 41, 31.CrossRefGoogle Scholar
Holsopple, K. 1982 M.S. thesis, The Pennsylvania State University.Google Scholar
Kawai, K., Kronast, B. & Pietrysk, Z. A. 1988 Bull. Am. Phys. Soc. 33, 2001.Google Scholar
Keilhacker, M. 1970 Nucl. Fusion, 4, 287, 519.Google Scholar
Long, D., Dimock, D., Grek, B., McNeill, D., Paladino, R., Robinson, J. & Tolnas, E. 1985 Rev. Sci. Instrum. 56, 1015.Google Scholar
Longmire, C. L. 1963 Elementary Plasma Physics, p. 90. Interscience.Google Scholar
Miyamoto, K. 1980 Plasma Physics for Nuclear Fusion, p. 96. MIT Press.Google Scholar
Rej, D. & Armstrong, W. 1984 Nucl. Fusion, 24, 177.CrossRefGoogle Scholar
Salzmann, H., Hirsch, K., Nielsen, P., Gowers, C., Gadd, A., Gadeberg, M., Murmann, H. & Schrodter, C. 1987 Nucl. Fusion, 71, 1925.Google Scholar
SAS 1985 SAS/Graph User's Guide, Version 5, p. 60. SAS Institute Inc., Cary, North Carolina.Google Scholar
Sheffield, J. 1976 Scattering of Electromagnetic Radiation by Plasmas, p. 62. Academic Press.Google Scholar
Shieh, D. R. 1985 Ph.D. dissertation, The Pennsylvania State University.Google Scholar
Shieh, D. R. & York, T. M. 1984 Proceedings of the 6th U.S. Symposium on Compact Toroid Research, ed. M. Yamada, and R. Ellis, Jr., Princeton University, p. 182. Princeton, New Jersey, 20 23 February 1984.Google Scholar
Siemon, R. et al. 1986 Fusion Technol. 9, 13.Google Scholar
Slough, J. T., Hoffman, A. L., Milroy, R. D., Harding, D. G. & Steinhauer, L. C. 1984 Nucl. Fusion, 24, 1537.Google Scholar
Spencer, R. L. & Tuszewski, M. 1985 Phys. Fluids, 28, 1810.Google Scholar
Sperling, J. L., Glassman, A. J., Moses, K. G. & Quon, B. H. 1986 Fusion Technol. 10, 78.CrossRefGoogle Scholar
Spitzer, L. 1962 Physics of Fully Ionized Gases, p. 110. Wiley.Google Scholar
Staudenmeier, J. 1986 Masters thesis, The Pennsylvania State University.Google Scholar
Steinhauer, L. C. 1981 Phys. Fluids, 24, 328.CrossRefGoogle Scholar
Steinhauer, L. C. 1986 Phys. Fluids, 29, 3379.CrossRefGoogle Scholar
Tuszewski, M. & Linford, R. K. 1982 Phys. Fluids, 25, 765.CrossRefGoogle Scholar
Trszkwski, M. & Wright, B. L. 1989 Phys. Rev. Lett., 63, 2236.Google Scholar
Webster, R., Okada, S., Tuszewski, M., Milroy, R., Crawford, E. & Barnes, D. 1988 Bull. Am. Phys. Soc. 33, 2067.Google Scholar
York, T. M. 1970 Rev. Sci. Instrum. 41, 519.CrossRefGoogle Scholar