Parametric Excitation of Whistler Waves by Circularly Polarized Electromagnetic Pumps in a Nonuniform Magnetoplasma: Modeling and Analysis
Possible generation of whistler waves by Tromsø HF heater in an overdense plasma having a density profile increasing linearly with altitude is investigated. Two coupled mode equations are derived and combined, after Laplace-transformed in time, into an equation in the form of the Schrödinger equation. Thus, the threshold field and growth rate of the instability can be determined by the eigenvalues of the eigenvalue equation defined by the Bohr-Sommerfeld quantization condition. It is shown that the HF heater wave of both R-H and L-H polarizations can parametrically decay into whistler wave and a Langmuir sideband. The Langmuir sideband is an anti-Stokes (i.e., frequency upshifted) line in the case of the R-H (o-mode) pump, while it is a Stokes (i.e., frequency downshifted) line when an L-H (x-mode) pump is employed. Since whistler waves have a broad range of frequency, the simultaneously excited Langmuir waves can have a much broader frequency bandwidth than those excited by the parametric decay instability and can be either frequency-upshifted or downshifted.
Unable to display preview. Download preview PDF.
- Frolov, V.L., 1990 URSI General Assembly, private communication.Google Scholar
- Kuo, S.P. and Lee, M.C., 1983, “Earth’s Magnetic Field Fluctuations Produced by Filamentation Instabilities of Electromagnetic Heater Waves,” J. Geophys. Res., 10:979.Google Scholar
- Kuo, S.P. and Barker, R.J., 1990 “Parametric Excitation of Whistler Wave and Frequency Upshifted Langmuir Sideband by L-H Circularly Polarized HF Heater,” XXIII General Assembly of URSI, Prague, Czechoslovakia, Aug. 27-Sept. 5, 1990.Google Scholar
- Landau, L.D. and Lifshitz, E.M., 1965, Quantum Mechanics, Nonrelativistic Theory, Pergamon Press, Oxford.Google Scholar