| Abstract: | The energetics of the excitation of the Farley-Buneman instability is considered, which is recently observed in the auroral and equatorial E regions of the Earth's ionosphere at altitudes between 100 km and 120 km. In the magnetic field of the Earth the Farley-Buneman instability is excited under the condition of a strong enough external electric field in the case of ion-neutral collisions with frequencies much larger than the ion gyrofrequency and electron-neutral collisions with frequencies much below the electron gyrofrequency. It is shown that the linear increase of the wave amplitudes is caused by a small disbalance between the processes of nonlinear energy pumping into the wave from an external electric field and the energy loss because of the collisions of the electrons and ions with the neutral particles. During the nonlinear energy pumping energy of the external electric field is transferred into a nonlinear current of second order, which is connected with the oscillating motion of the electrons in the wave. The oscillating electron motion takes place perpendicular to wave propagation. 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. A new and simply to understand derivation of the anomalous diffusion coefficient is presented, related to the study of the behaviour of a test wave with frequency much above the frequencies of the Farley-Buneman turbulence in developed stage can cause an additional macroscopic nonlinear Pedersen current directed along the external electric field. It is found that the nonlinear Pedersen current can reach the order of the usual Pedersen current and should contribute to the effective heating of the ionospheric plasma. |
