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Measurement of non-Maxwellian electron velocity distributions in a reflex discharge

Published online by Cambridge University Press:  13 March 2009

C. R. Phipps Jr
Affiliation:
University of California, Los Alamos Scientific Laboratory, Los Alamos, NM 87544
D. Bershader
Affiliation:
Deparment of Aeronautics and Astronautics, Leland Stanford Junior University, Stanford, California 94305

Abstract

Thomson scattering was used to determine space- and time-resolved electron velocity distribution components parallel and transverse to the magnetic field direction in a Penning-type reflex discharge in hydrogen. Electron densities were of the order 1013 cm-3, and temperatures about 3eV. For magnetic field strengths less than about 200 G, Maxwellian distributions were obtained over an energy range six times the thermal energy. Temperatures were in excellent agreement with Langmuir probe data. However, for fields of about 4500 G chaotic plasma potentials were observed with the Langmuir probe. In this regime, in which the plasma was unstable, Thomson scattering showed electron velocity distributions having central temperatures of about 2eV and wing temperatures of 15–20 eV. The experiment design employed led to extremely low stray light levels permitting clean measurements at the laser wavelength and detection of scattered signals as faint as two photons.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1978

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References

REFERENCES

Bekefi, G.M 1966 Radiation Processes in Plasmas, p. 73. Wiley.Google Scholar
Briffod, G., Gregoire, M. & Gruber, S. 1964 Plasma Phys. 6, 329.Google Scholar
Evans, D. E. & Katzenstein, J. 1969 Rep. Prog. Phys. 32, 207.Google Scholar
Fejer, J. A. 1961 Can. J. Phys. 30, 716.Google Scholar
Fishkova, T. Ya., Shpak, E. V. & Yavor, S. Ya. 1964 Soviet Phys. Tech. Phys. 9, 40.Google Scholar
Forrest, M. J., Peacock, N. J., Robinson, D. C., Sannikov, V. V. & Wilcock, P. D. 1970 Culham Laboratory, Rep. CLM-R 107.Google Scholar
Glasstone, S. & Lovberg, R. H. 1960 Controlled Thermonuclear Reactions. Van Nostrand.Google Scholar
Hoh, F. C. & Lehnert, B. 1961 Phys. Rev. Lett. 7, 75.CrossRefGoogle Scholar
Hooper, E. B. 1969 Advances in Electronics and Electron Physics, 27, 295.CrossRefGoogle Scholar
Katz, J. I., Weinstock, J., Kruer, W. L., Degroot, J. S. & Faehl, R. 1973 Phys. Fluids, 16, 1519.CrossRefGoogle Scholar
Kegel, W. H. 1970 Plasma Phys. 12, 295.CrossRefGoogle Scholar
Koons, H. C. & Fiocco, G. 1968a J. Appl. Phys. 39, 3389.Google Scholar
Koons, H. C. & Fiocco, G. 1968b Phys. Lett. 26 A, 614.Google Scholar
Kruer, W. L., Kaw, P. K., Dawson, J. M. & Oberman, C. 1970 Phys. Rev. Lett. 24, 987.Google Scholar
Kunze, H. J. 1968 Plasma Diagnostics (ed. Lochte-Holtgreven, W.), p. 550. North Holland.Google Scholar
McCormick, G. & Lidsky, L. M. 1971 Proc. Conf. Hollow Cathode Discharges and Their Applications, Orsay, p. 43.Google Scholar
Penning, F. M. 1937 Physica, 4, 71.CrossRefGoogle Scholar
Phipps, C. R. & Bershader, D. 1973 Dynamics of Ionized Gases (ed. Lighthill, M. J., Imai, I. & Sato, H.), p. 257. University of Tokyo Press.Google Scholar
Thomassen, K. I. 1966 Phys. Fluids, 9, 626.CrossRefGoogle Scholar