Hostname: page-component-cd9895bd7-gbm5v Total loading time: 0 Render date: 2024-12-26T20:37:27.624Z Has data issue: false hasContentIssue false
  • English
  • Français

Electric fields parallel to the magnetic field in a laboratory plasma in a magnetic mirror field

Published online by Cambridge University Press:  13 March 2009

R. Geller ,
N. Hopfgarten ,
B. Jacquot  and
C. Jacquot
R. Geller
Affiliation:
Association EURATOM–CEA, Départment de Physique du Plasma et de la Fusion Contr⊚lée, Service Ionique Générale, Centre d'Etudes Nucléaires, B.P. 85, Centre de Tri 38041, Grenoble Cedex
N. Hopfgarten
Affiliation:
Association EURATOM–CEA, Départment de Physique du Plasma et de la Fusion Contr⊚lée, Service Ionique Générale, Centre d'Etudes Nucléaires, B.P. 85, Centre de Tri 38041, Grenoble Cedex
B. Jacquot
Affiliation:
Association EURATOM–CEA, Départment de Physique du Plasma et de la Fusion Contr⊚lée, Service Ionique Générale, Centre d'Etudes Nucléaires, B.P. 85, Centre de Tri 38041, Grenoble Cedex
C. Jacquot
Affiliation:
Association EURATOM–CEA, Départment de Physique du Plasma et de la Fusion Contr⊚lée, Service Ionique Générale, Centre d'Etudes Nucléaires, B.P. 85, Centre de Tri 38041, Grenoble Cedex
Get access Rights & Permissions [Opens in a new window]

Abstract

With electrostatic probes, the electric field component E∥ along the magnetic field B was comprehensively investigated in a collisionless plasma, the density of which was of the order of 1010 cm-3. The plasma in the experiment has several properties in common with the plasma of the ionosphere/magnetosphere scaled to laboratory dimensions. It is produced by means of electron cyclotron resonance in a microwave cavity located in the magnetic field gradient in one half of a magnetic mirror field. The magnetic field strength is 3600G in the resonance zone and 1800G in the middle of the mirror field. The measurements show that a stationary E∥ exists everywhere in the plasma, where the magnetic field gradient grad11 B in the direction of the field is different from zero. The direction of E‖ is opposite to that of grad‖B. The total potential drop along B between the resonance zone and the midplane of the mirror field is of the order of kilovolts. E‖ accelerates ions along B to energies of the order of kilo electron volts. Experimental parameters of importance for the production of E‖ are the neutral gas pressure p (normally a few times 10− Torr), the microwave power (usually about 2kW), and the mirror ratio γ in the mirror region opposite to the cavity side, γ was normally <2. For γ>2·3, an instability develops and no stationary E‖ remains. As p is increased, E‖ decreases successively. In terms of the mean free path λ, it is found that λ>5−10L is a necessary condition for the existence of E‖. L is twice the distance between the cavity and the midplane of the mirror field. In the experiment, the ion and electron pitch angle distributions are forced to be different; the ion velocity is mainly parallel to B, and the electron velocity essentially perpendicular to JB, and as consequence E‖ is created. In this way an experimental demonstration is presented of the theoretically predicted relation between E‖ and the pitch angle distributions. When imposing sufficiently strong radial electric fields Er (fields perpendicular to B), the distribution of the potential along B is deformed, probably due to changes in the particle distributions caused by E‖. We think that our results strongly support the idea that Et is produced in the magnetosphere, and is at least sometimes an important mechanism for the acceleration and precipitation of auroral particles.

Type
Research Article
Information
Journal of Plasma Physics , Volume 12 , Issue 3 , December 1974 , pp. 467 - 486
Copyright
Copyright © Cambridge University Press 1974

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

Abgrall, F., Bardet, R.&; Gormezano, C. 1968 IIème Colloque International sur les Interactions entre le Champs Oscillants et les Plasmas, Saclay, vol. 2, p. 643.Google Scholar
Albert, R. D. 1967 J. Geophys. Res. 72, 5811.CrossRefGoogle Scholar
Alfvén, H.&; Fälthammer, C. G. 1963 Cosmical Electrodynamics (2nd edn.). Clarendon.Google Scholar
Bardet, R., Consoli, T.&; Geller, R. 1964 Nucl. Fusion, 4, 48.CrossRefGoogle Scholar
Bardet, R., Consoli, T.&; Geller, R. 1965 Nucl. Fusion, 5, 7.CrossRefGoogle Scholar
Bendaniel, D. J. 1961 Plasmas Phys. 3, 235.Google Scholar
Bosqued, J. M., Cardena, G., Reme, H.&; Souleille, P. 1971 C.R. Acad. Sci. B 273,933.Google Scholar
Canobbio, E.&; Finzi, U. 1968 IIème Colloque International sur les Interactions entre le Champs Ocillants et les Plasmas, Saclay, vol. 2, p. 605.Google Scholar
Consoli, T.&; Hall, R. B. 1963 Nucl. Fusion, 3, 237.CrossRefGoogle Scholar
De Barbieri, O. 1972 Proc. 5th European Conf. on Controlled Fusion and Plasma Phys., Grenoble, vol. 1, p. 87.Google Scholar
De Forest, S. E.&; McIlwain, C. E. 1971 J. Geophys. Res. 76, 3587.CrossRefGoogle Scholar
Evans, D. S. 1968 J. Geophys. Res. 73, 2315.CrossRefGoogle Scholar
Geller, R., Hess, W. R., Hess, M., Jacquot, B.&; Jacquot, C. 1972 Proc. 5th European Conf. on Controlled Fusion and Plasma Phys., Grenoble, vol. 1, p. 123.Google Scholar
Geller, R., Jacquot, B.&; Jacquot, C. 1970 Proc. 4th European Conf. on Controlled Fusion and Plasma Phys, Rome, p. 97. CNEN Divisione Affari Internazionali e Studi Economici, Officio Edizioni Scientifiche.Google Scholar
Geller, R., Jacquot, B.&; Jacquot, C. 1971 Plasma Phys. and Controlled Nucl. Fusion Res, vol. 2, p. 631. Vienna: International Atomic Energy Agency.Google Scholar
Geller, R., Jacquot, B.&; Jacquot, C. 1974 Phys. Fluids. (To be published.)Google Scholar
Geller, R.&; Leroy, C. 1970 Etude d'une Instabilité Observée, Rapport d' Activité du Groupe de Recherches, IIème Partie, Grenoble, p. 34. Association Euratom-CEA, Department de Physique du Plasma et de la Fusion Contr⊚ée, Fontenay-aux-Roses.Google Scholar
Hess, W. R. 1972 Dr Ing, thesis, University of Stuttgart.Google Scholar
Hopfgarten, N., Johansson, R. B., Nilsson, B. H.&; Persson, H. 1972 Proc. 5th European Conf. on Controlled Fusion and Plasma Phys., Grenoble, vol. 1, p. 88.Google Scholar
Hultqvist, B., Borg, H., Riedler, W.&; Christophersen, P. 1971 Planet. Space Sci. 19, 279.CrossRefGoogle Scholar
Katz, L.&; Rothwell, P. L. 1968 Phys. Rev. Letters, 21, 1764.CrossRefGoogle Scholar
Kelly, M. C., Mozer, F. S.&; Fahleson, U. V. 1971 J. Geophys. Res. 76, 6054.CrossRefGoogle Scholar
Kesner, J. 1973 Plasma Phys. 15, 577.CrossRefGoogle Scholar
Marx, K. D. 1970 Phys. Fluids, 13, 1355.CrossRefGoogle Scholar
Mozer, F. S.&; Bruston, P. 1966 J. Geophys. Res. 71, 4461.CrossRefGoogle Scholar
Mozer, F. S.&; Fahleson, U. V. 1970 Planet. Space Sci. 18, 1563.CrossRefGoogle Scholar
Persson, H. 1963 Phys. Fluids, 6, 1756.CrossRefGoogle Scholar
Persson, H. 1966 Phys. Fluids, 9, 1090.CrossRefGoogle Scholar
Post, R. F. 1961 Phys. Fluids, 4, 902.CrossRefGoogle Scholar
Rees, M. H. 1969 Space Sci. Rev. 10, 413.CrossRefGoogle Scholar
Rème, H & Bosqued, J. M. 1971 J. Geophys. Res. 76, 7683.CrossRefGoogle Scholar
Rose, D. J.&; Clark, M. 1961 Plasmas and Controlled Fusion. MIT.Google Scholar
Sharp, R. D.&; Johnson, R. G. 1968 Earth's Particles and Fields (ed. McCormac, B. M.), p. 113. Reinhold.Google Scholar
Yushmanov, E. E. 1966 Soviet Phys. JETP, 22, 409.Google Scholar