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Monte Carlo calculations for transport due to MHD modes

Published online by Cambridge University Press:  13 March 2009

Alkesh Punjabi
Affiliation:
Hampton University, Hampton, Virginia 23668, U.S.A.
Allen Boozer
Affiliation:
College of William and Mary, Williamsburg, Virginia 23185, U.S.A.
Maria Lam
Affiliation:
Hampton University, Hampton, Virginia 23668, U.S.A.
Myung-Hee Kim
Affiliation:
Hampton University, Hampton, Virginia 23668, U.S.A.
Kathy Burke
Affiliation:
Hampton University, Hampton, Virginia 23668, U.S.A.

Abstract

The three basic mechanisms that produce either classical or anomalous transport are spatial variation of magnetic field strength, spatial variation of electrostatic potential in magnetic surfaces, and loss of magnetic surfaces. A Monte Carlo code is written to study transport due to these three mechanisms interacting with collisional effects. The equations of motion are obtained from the canonical drift Hamiltonian, but non-canonical co-ordinates are used to simplify the integrations. The code is applied to the reversed-field-pinch ZT-40 and the Tokapole II. For ZT-40 the Bessel-function model is used to represent the magnetic field geometry. The effects of pitch-angle scattering, loop voltage and the break-up of magnetic surfaces resulting from resistive MHD perturbations on the drift particle trajectories are illustrated. The particle diffusion coefficients are obtained for varying amplitudes of resistive MHD perturbations. For Tokapole II the spectrum of both the ideal and resistive MHD perturbations is constructed from the experimental data. The drift trajectories for trapped and passing electrons in the presence of such perturbations are obtained. The particle diffusion coefficients for the neo-classical regime in Tokapole II are obtained for varying collision frequency. By comparing the transport coefficients for various groups of particles with the experimental data, we hope to obtain far more information on the transport mechanisms than can be obtained by the standard confinement time measurements. The various groups of particles that can be studied using the code include runaway electrons, thermal electrons, and both passing and trapped diagnostic beam ions.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1990

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References

REFERENCES

Bodin, H. A. B. & Newton, A. A. 1980 Nucl. Fusion, 20, 1255.CrossRefGoogle Scholar
Boozer, A. H. 1982 Phys. Fluids, 25, 520.CrossRefGoogle Scholar
Boozer, A. H. & Petravic, G. K. 1981 Phys. Fluids, 24, 851.CrossRefGoogle Scholar
Cary, J. R. & Kotschenereuther, M. 1985 Phys. Fluids, 28, 1392.CrossRefGoogle Scholar
Graessle, D. E., Prager, S. C. & Dexter, R. N. 1989 Phys. Rev. Lett. 62, 535.CrossRefGoogle Scholar
Kadomtsev, B. B. 1975 Soviet J. Plasma Phys. 1, 389.Google Scholar
Kadomtsev, B. B. & Pogutse, O. P. 1973 Proceedings of 6th European Conference on Controlled Fusion and Plasma Physics, ed. Kadomtsev, B. B., Joint Institut of Nuclear Research, Moscow, vol. 1, p. 59.Google Scholar
Kovrizhnykh, L. M. 1984 Nucl. Fusion, 24, 851.CrossRefGoogle Scholar
Liewer, O. C. 1985 Nucl. Fusion, 25, 543.CrossRefGoogle Scholar
Ling, K. M. & Baker, D. A. 1986 Math. Modeling, 7, 429.CrossRefGoogle Scholar
Pare, V. K. 1986 Basic Physical Processes of Toroidal Fusion Plasmas (Proceedings of Workshop at Varenna, Italy, 1985) (ed. Lampis, G. P., Lontano, M., Leotta, G., Malein, A. & Sindoni, E.), p. 577. Euratom.Google Scholar
Pytte, A. & Boozer, A. H. 1981 Phys. Fluids, 24, 88.CrossRefGoogle Scholar
Rechester, A. B. & Rosenbluth, M. N. 1978 Phys. Rev. Lett. 40, 38.CrossRefGoogle Scholar
Wesson, J. A. 1986 Basic Physical Processes of Toroidal Fusion Plasmas (Proceedings of Workshop at Varenna, Italy, 1985) (ed. Lampis, G. P., Lontano, M., Leotta, G., Malein, A. & Sindoni, E.), p. 569. Euratom.Google Scholar