Hostname: page-component-78c5997874-j824f Total loading time: 0 Render date: 2024-11-12T22:19:42.449Z Has data issue: false hasContentIssue false

On the generation of quasi-electrostatic half-electron-gyrofrequency VLF emissions in the magnetosphere

Published online by Cambridge University Press:  13 March 2009

Norichika Ohmi
Affiliation:
Research Institute of Atmospherics, Nagoya University, Toyokawa, Aichi, 442, Japan
Masashi Hayakawa
Affiliation:
Research Institute of Atmospherics, Nagoya University, Toyokawa, Aichi, 442, Japan

Abstract

A theoretical study is made of the generation mechanism of quasi-electrostatic VLF emissions observed in the distant magnetosphere, with frequency greater than half the electron gyrofrequency and with wave normal around the cold plasma oblique resonance cone. The two-component plasma is treated, composed of cold electrons and hot electrons with bi-Maxwellian and loss-cone distribution functions. The effects of various plasma parameters on the instability characteristics are examined in order to estimate their relative importance in determining the properties of unstable waves. It is found that both types of hot plasma distribution function can account for quasi-electrostatic half-gyrofrequency emissions. The frequency where the maximum growth rate occurs is mainly determined by the temperature anisotropy of the hot plasma, and the wave normal angle where maximum growth is expected is determined by the temperature of the hot plasma and the ratio of the cold to hot plasma densities. These theoretical considerations form the basis of a suggested plasma model which is able to explain our experimental direction-finding results.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1986

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

Ashour-Abdalla, M. & Cowley, S. W. H. 1974 Magnetospheric Physics (ed. MeCormac, B. M.), p. 241. Reidel.CrossRefGoogle Scholar
Ashour-Abdalla, M. & Kennel, C. F. 1978 J. Geophys. Res. 83, 1531.CrossRefGoogle Scholar
Burtis, W. J. & Helliwell, R. A. 1976 Planet. Space Sci. 24, 1007.CrossRefGoogle Scholar
Cornilleau-Wehrlin, N., Gendrin, R., Lefeuvre, F., Parrot, M., Grard, R., Jones, D., Bahnsen, A., Ungstrup, E. & Gibbons, W. 1978 Space Sci. Rev. 22, 371.Google Scholar
Coroniti, F. V., Fredricks, R. W., Kennel, C. F. & Scarf, F. L. 1970 J. Geophys. Res. 76, 2366.CrossRefGoogle Scholar
Curtis, S. A. 1978 J. Geophys. Res. 83, 3841.CrossRefGoogle Scholar
Decreau, P. M. E., Etcheto, E. J., Knott, K., Pedersen, A., Wrenn, G. L. & Young, D. T. 1978 Space Sci. Rev. 22, 633.Google Scholar
Dury, R. A., Guest, G. E. & Harris, E. G. 1965 Phys. Rev. Lett. 14, 131.CrossRefGoogle Scholar
Guest, G. E. & Sigmar, D. J. 1971 Nucl. Fusion, 11, 151.CrossRefGoogle Scholar
Harris, E. G. 1961 J. Nucl. Energy, Part C, 2, 138.CrossRefGoogle Scholar
Hasegawa, A. 1975 Plasma instabilities and nonlinear effects, p. 68. Springer.CrossRefGoogle Scholar
Hashimoto, K. & Kimura, I. 1981 J. Geophys. Res. 86, 11, 148.Google Scholar
Hayakawa, M., Yamanaka, Y., Parrot, M. & Lefeuvre, F. 1984 J. Geophys. Res. 89, 2811.CrossRefGoogle Scholar
Karpman, V. I., Alekhin, Ju. K., Borisov, N. D. & Rjabova, N. A. 1973 Astrophys. Space Sci. 22, 267.CrossRefGoogle Scholar
Kennel, C. F. & Petscheck, H. E. 1966 J. Geophys. Res. 71, 1.CrossRefGoogle Scholar
Kennel, C. F., Scarf, F. L., Fredricks, R. W., Geehee, J. H. & Coroniti, F. V. 1970 J. Geophys. Res. 75, 6136.CrossRefGoogle Scholar
Kennel, C. F. & Ashour-Abdalla, M. 1982 Magnetospheric Plasma Physics (ed. Nishida, A.), p. 297. Centre for Academic Publishing, Japan.Google Scholar
Koons, H. C. 1981 J. Geophys. Res. 86, 6745.CrossRefGoogle Scholar
Maeda, K. 1976 Planet. Space Sci. 24, 341.CrossRefGoogle Scholar
Ronnmark, K. 1982 Kiruna Geophys. Inst. Report, No. 179.Google Scholar
Shima, Y. & Hall, L. S. 1965 Phys. Rev. A, 139, 1115.CrossRefGoogle Scholar
Stix, T. H. 1962 The Theory of Plasma Waves. McGraw-Hill.Google Scholar
Tsurutani, B. T. & Smith, E. J. 1974 J. Geophys. Res. 79, 118.CrossRefGoogle Scholar
Young, T. S. T. 1974 J. Geophys. Res. 79, 1985.CrossRefGoogle Scholar