Hostname: page-component-cd9895bd7-gvvz8 Total loading time: 0 Render date: 2024-12-27T14:43:36.151Z Has data issue: false hasContentIssue false
  • English
  • Français

Large-Debye-distance effects in a homogeneous plasma

Published online by Cambridge University Press:  13 March 2009

Jan Scheffel  and
Bo Lehnert
Jan Scheffel
Affiliation:
The Royal Institute of Technology, S-100 44 Stockholm, Sweden
Bo Lehnert
Affiliation:
The Royal Institute of Technology, S-100 44 Stockholm, Sweden
Get access Rights & Permissions [Opens in a new window]

Abstract

The classical phenomenon of electron plasma oscillations has been investigated from new aspects. The applicability of standard normal-mode analysis of plasma perturbations has been judged from comparisons with exact numerical solutions to the linearized initial-value problem. We consider both Maxwellian and non-Maxwellian velocity distributions. Emphasis is on perturbations for which αλD is of order unity, where α is the wavenumber and λD the Debye distance. The corresponding large-Debye-distance (LDD) damping is found to substantially dominate over Landau damping. This limits the applicability of normal-mode analysis of non-Maxwellian distributions. The physics of LDD damping and its close connection to large-Larmor-radius (LLR) damping is discussed. A major discovery concerns perturbations of plasmas with non-Maxwellian, bump-in-tail, velocity distribution functions f0(ω). For sufficiently large αλD (of order unity) the plasma responds by damping perturbations that are initially unstable in the Landau sense, i.e. with phase velocities initially in the interval where df0/dw > 0. It is found that the plasma responds through shifting the phase velocity above the upper velocity limit of this interval. This is shown to be due to a resonance with the drifting electrons of the bump, and explains the Penrose criterion.

Type
Research Article
Information
Journal of Plasma Physics , Volume 41 , Issue 3 , June 1989 , pp. 493 - 516
Copyright
Copyright © Cambridge University Press 1989

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

Backus, G. 1960 J. Math. Phys. 1, 178.CrossRefGoogle Scholar
Bernstein, B., Greene, J. & Kruskal, M. 1957 Phys. Rev. 108, 546.CrossRefGoogle Scholar
Derfler, H. & Simonen, T. C. 1966 Phys. Rev. Lett. 17, 172.CrossRefGoogle Scholar
Dawson, J. 1961 Phys. Fluids, 4, 869.CrossRefGoogle Scholar
Jackson, J. D. 1960 J. Nucl. Energy, C 1, 171.CrossRefGoogle Scholar
Jones, W. D., Doucet, H. J. & Buzzi, J. M. 1985 An Introduction to the Linear Theories and Methods of Electrostatic Waves in Plasmas. Plenum.CrossRefGoogle Scholar
Krall, N. & Trivelpiece, A. 1973 Principles of Plasma Physics. McGraw-Hill.Google Scholar
Landau, L. 1946 J. Phys. 10, 45.Google Scholar
Lehnert, B. 1985 The Royal Institute of Technology, Stockholm, TRITA-PFU-85–05.Google Scholar
Lewak, G. J. 1969 J. Plasma Phys. 3, 243.Google Scholar
Malmberg, J. H. & Wharton, C. B. 1964 Phys. Rev. Lett. 13, 184.CrossRefGoogle Scholar
Montgomery, D. 1964 Phys. Fluids, 7, 477.CrossRefGoogle Scholar
Penrose, O. 1960 Phys. Fluids 3, 258.CrossRefGoogle Scholar
Thomson, J. J. & Thomson, G. P. 1933 Conduction of Electricity through Gases, p. 353. Cambridge University Press.Google Scholar
Tonks, L. & Langmuir, I. 1929 Phys. Rev. 33, 195.Google Scholar
van Kampen, N. 1955 Physica, 21, 949.Google Scholar
Vlasov, A. A. 1938 Zh. Eksp. Teor. Fiz. 8, 291.Google Scholar