VLF emission in the region of the polar cusp

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Author
Golikov, Yu. V.
Troitskaya, V. A.
Pustovalov, V. V.
Heacock, Richard R.
Hessler, V. P. (Victor Peter)
Keyword
VLF emissions
Antarctic regions
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URI
http://hdl.handle.net/11122/15479
Description
UAG R-261; Summary: Recordings of VLF noise at a number of ground-based stations in Antarctica show the existence of a region of higher intensity under the polar cusp. The generation of this emission is thought to be connected with fluxes of electrons penetrating the cusp. A nonlinear theory of generation of the VLF noise by electron fluxes in the polar magnetosphere is proposed. Two modes of oscillation are considered, waves at the frequency of the lower hybrid resonance (5 kHz-100 kHz) and whistler mode waves in the range of several kHz. The spectral distribution and the level of turbulence are consistent with the assumption that they are due to two interpenetrating electron fluxes in the magnetized plasma at lower hybrid resonance (LHR) frequencies. It is shown that the quasistationary level of the noise oscillates in time. The theoretical energy density of the oscillation is in agreement with experimental data obtained in the cusp. Some aspects of the generation of the whistlers by electron fluxes are discussed. The increment of parametric excitement of whistlers by electrostatic oscillations at the frequencies of LHR is calculated. The experimental data of VLF emission from satellites and at ground-based stations are considered in the frames of the proposed theory. A new method of ground-based diagnostic of the parameters of the electron fluxes penetrating the cusp is suggested.
Table of Contents
Summary – Introduction – I. Apparatus and experimental data – II. Non-linear effects of VLF noise generation by electron beams in polar magnetosphere – A. Turbulent noise at frequencies near LHR – B. Investigation of whistler excitation conditions in the polar region – C. Propagation nearly across the magnetic field -- Conclusion – Appendix – Acknowledgements – References.
Date
1978-08
Publisher
Geophysical Institute at the University of Alaska Fairbanks
Type
Report
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