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.

b . А low and sharp onset of the EDFA can be expected due to the electron nonisothermality (Gurevich and Karashtin, 1984). c. A microstructure of the scatter volume. If the auroral electrojet has a "filamental" structure (Siren et al., 1977) then the scatter volume could be filled with a number of patches uhere the ionospheric parameters are different. The uave scale for such irregularities are rather uide. from tens of meters to tens of kilometers. It seems that similar signatures one can see directly from data by Farley and Balsley (1973) for their radar experiment in equatorial ionosphere (Farley and Balsley, 1973). The artist picture of the jet filaments (or patches) filling the radar collecting areas is shown in RHS of Fig.3. Since the ionospheric parameters in and outside of patches are apparently different then the instability conditions are different there too. So, at least qualitatively, the sharp jump mentioned can be transformed to the soft E-field threshold. This feature can be a principal and strong thing masking (cisfocusing) the real E-field threshold of the FB irregularities. Let's illustrate this point by a simple model, Fig.3. It suggests inside of the scatter volume Vs there exists large- middle scale irregularities of electron density with typical wavelength 0.1 < L < V km. For the STARE radars the scatter volume is 15x50x10 km , where the numbers mean its size along and across of the radar beam and the vertical one. Now we consider that the filaments are aligned along the Hall electron flow. So, going across the filaments one >can see electron density variations which we suggest to be distributed randomly. Let's take a random component, X with the normal distribution having zero mean, < X > = 0 and the standard deviation, <X2> = 1- Then the equation for the electron density, N(X ) is N ( x ) = No (1 - mx) , where ГП is the relative value of the random component and N q is the electron density mean value. If we neglect the field-aligned current then the E-field is the following (from the current flow continuity equation) 23