Nonlinear mechanism of the generation of lower hybrid waves in cosmic plasmas

1Yukhimuk, AK, 2Fedun, VN, 3Yukhimuk, VA, 2Fal'ko, OG, 1Sirenko, EK
1Main Astronomical Observatory of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
2Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
3Taras Shevchenko National University of Kyiv, Kyiv, Ukraine; Newcastle University , Newcastle, Australia
Kosm. nauka tehnol. 1998, 4 ;(5):41–45
Publication Language: Russian
A new nonlinear mechanism of the generation of kinetic Alfven waves and lower hybrid waves in magnetized plasma with a small plasma parameter (β =8πnT/B0 2<1) is investigated. The parametric instability, where the whistler wave is the pumping wave, is considered as the generation mechanism. Two-fluid magnetohydro-dynamics is used for describing the nonlinear parametric interaction of waves. A nonlinear dispersion equation for the coupling of the lower hybrid and kinetic Alfven waves is found. We defermined also the instability growth rate у and the amplitude threshold value for the pump wave. The investigation suggests that taking into account the kinetic effects in the Alfven waves (the finite ion Larmour radius and the electron inertia length) is essential for parametric interaction of waves. It is well known that whistlers modes are use for additional plasma heating. The idea of plasma heating throunh the parametric decay implies that the energy is transmitted to plasma from waves. Very often the products of the decay can be absorb more effectively than the pump wave itself. Thus the kinetic Alfven waves interact actively with plasma particles and heat the plasma. The lower hybrid waves also interact actively with ions and increase their energy component perpendicular to the external magnetic field. They may be responsible for the temperature anisotropy and acceleration of heavy ions. Our results are used for analyzing experimental data for cosmic plasmas.
Keywords: atmospheric physics, cosmic plasmas, mechanisms of waves generation
1. Sazhin S. S. Natural Radio Emissions in the Earth's Magnetosphere, 155 p. (Nauka, Moscow, 1982) [In Russian].
2. Yukhimuk A. K., Fal'ko O. G., Yukhimuk V. A., et al. Nonlinear interection of alfven waves and ionic acoustic waves in a magnetized plasma. Kosm. nauka tehnol., 2 (3-4) 44—48 (1996) [in Russian].
3. Barrington R. E., Berlose G. S. Preliminary results from the very-low-frecuency reciver on board Canadas Alouette satellite. Nature, 198, 651—656 (1963).
4. Bell T. F., Inan U. S., Lauben D., et al. DE-1 and COSMOS 1809 observations of lower hybrid waves excited by VLF whistler mode waves. Geophys. Res. Lett., 21 (8), 653—656 (1994).
5. Berger R. L., Chen L. Exitation of fast waves by slow waves near the lower-hybrid  frecuency. Phys. Fluids, 19, 1392—1399 (1976).
6. Brice N. M., Smith R. L. Recordings from satellite Alouette-2-A very low frecuency plasma  resonance. Nature, 203, 926—927 (1964).
7. Bujarbarua S., Shukla P. K. Exitation of ULF and VLF waves in the ionosphere. Planet. Space Sci., 28, 1051 — 1058 (1980).
8. Gurnett D. A. A satellite study of VLF hiss. J. Geophys. Res., 71 (23), 5599—5615 (1966).
9. Guha S., Sarkar R. Parametric decay of a whistler wave at the difference frecuency of two electromagnetic waves in a plasma. J. Plasma. Physics, 47 (1), 115—123 (1991).
10. Leyser T. B. Parametric interaction between hybrid and low hybrid waves in heating experiments. Geophys. Res. Lett., 18 (3), 408—411 (1991).
11. Murtaza G., Shukla P. K. Nonlinear generation of electromagnetic waves. J. Plasma Phys., 31, 423—436 (1984).
12. Scarf F. L., Fredrics R. W., Smith E. J. et al. OGO-5 observations of LHR noise emissions and wistlers near the plasmapause at several Earth radii during a large magnetic storm. J. Geophys. Res., 77 (10), 1776— 1793 (1972).
13. Shukla P. K., Stenflo L. Nonlinear Alfven waves. Physica Scripta, 60, 32—35 (1995).
14. Shukla P. K., Mamedow M. A. Nonlinear decay of a propagating lower-hybrid wave in a plasma. J. Plasma Physics, 19 (1), 87—96 (1978).
15. Stenflo L. Simulated scattering of large amplitude waves in the ionosphere. Physica Scripta, 30, 166—169 (1990).

16. Yukhimuk A. K., Kotsarenko N. Ya., Yukhimuk V. A. Nonlinear interaction of Alfven waves in solar atmosphere. Stydy of the Solar-Terrestrial system: Proc. 26th ESLAB Symp., Killarny, 16—19 June 1992, 337—341 (Noordwijk, 1992).