Кустов, А. В. О пороговом электрическом поле для возникновения авроральных неоднородностей с длиной волны около одного метра / А. Кустов, М. Успенский, И. Кангас ; Акад. Наук СССР, Кол. фил. им С. М. Кирова, Поляр. геофиз. ин-т. – Препр. ПГИ-87-06-60. - Апатиты : [б. и.], 1988.

the excitation of irregularities having another nature ( e.g. relating to the neutral atmospheric gas turbulence and so-called electron density mixing, Gershman (1974)) as well as on the irregularity Doppler velocities which are measured by radar. As for the neutral wind the possibility is obviously seen to excite FB irregularities when its drift velocity is close to гего. Such situation can be real (when the magnetospheric electric field is absent) if neutral wind is strong. Let's assume the threshold condition on the relative electron- ion drift velocity is satisfied. However the phase velocity of the FB- irregularities as the electron drift velocity itself should be here very close to zero. In the case of the moderate electric field as well as neutral wind and for its different mutual orientation one can expect different kinds of EDFA (E)-dependences, Nielsen et al.(1987>. That is why an investigation of auroral electrojet turbulence properties as a function of electric field using radar irregularity drift velocity data only can be involved in difficulties and uncertainities. In order to take into consideration the irregularities of another nature it is necessary to know the frequency dependence and the azimuth anisotropy for these irregularities. One of mechanisms for such irregularities formation is a turbulent mixing in the ionospheric plasma. These processes are very effective when horizontal and vertical gradients of electron density exist in the lower part of E-layer, Gershman (1974). Of course, the fluctuation amplitude of this kind of irregularities as a function of E-field can be different from the FB/GD EDFAs. Hence a sorting is needed of experimental data on different types of phenomena before their converting to the EDFA magnitudes. In our opinion the growing dependence of backscatter amplitude in a course of the drift velocities going through 50 - 200 m/s found by Andre (1983) from the б-day statistics ie an example of a random superpositon at least of the three effects. They are the dependence of backscatter amplitude on electron density; the dependence of irregularity drift velocity on> the magnitude and azimuth of magnetospheric electric field as well as of neutral wind and at last the mixing of the existing weak FB and GD irregularities with the other ones, e.g. that one relating to the atmospheric turbulense mixing (Nielsen et al., 1982). The latter can affect both the backscatter amplitudes and their irregularity drift velocities 26