München 1997 – wissenschaftliches Programm
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EP: Extraterrestrische Physik
EP 13: Atmosphäre/Ionosphäre 1
EP 13.6: Vortrag
Mittwoch, 19. März 1997, 17:45–18:00, 332
On the problem of anomalous polar E-region heating due to Farley-Buneman turbulence — •C.-V. Meister 1), V.A. Liperovsky 2), and A.V. Kustov 3) — 1) University Potsdam, WIP Space Plasma Physics, 2) Institute of Physics of the Earth Moscow, 3) University Saskatchewan, Institute of Space and Atmospheric Studies
The energetics of the excitation of Farley-Buneman waves in the E-region of the earth’s ionosphere at altitudes of 100-200 km is considered. In the geomagnetic field the Farley-Buneman instability is excited under the condition of a strong enough external electric field Eo in the case of ion-neutral collisions with frequencies above the ion-gyrofrequency and electron-neutral collisions much below the electron gyrofrequency. It is shown that the linear increase of the wave amplitude is caused by a small disbalance between the nonlinear energy pumping into the wave from Eo and the energy loss because of the collisions of the electrons and ions with the neutrals. During the nonlinear energy pumping, energy of Eo is transferred into a nonlinear current of second order, which is connected with the oscillating motion of the electrons in the wave. From the estimations follows that the energy pumped into a Farley-Buneman wave during one period of pulsation is much larger than the wave energy itself. Further it is shown, that the Farley-Buneman turbulence can cause an additional macroscopic nonlinear Pedersen current directed along Eo. This current may reach the order of the usual Pedersen current and should contribute to the effective heating of the ionospheric plasma.