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.

( 2 ) F2№ ) = 10 ' Ч’ (3) Zq.(2) 1 * mostly right for Jt = 2 and large E-fields, at least итоге than 20 mV/m. From experiments in the equatorial electrojet (Fejar and Kelley, I960) and in the auroral zone (Andre, 1983) it is known the azimuth anisotropy becoaes weaker when the E-field drops below 20 BV/m. That is why in our calculation vie assuiae Ж = 2 for E = 13-16 .iV/l; 1 for E = 10-13 mV/m and 0.5 for E = 5-10 mV/m. The numbers cited is the first approximation of the experimental data by Andre (19S3). One thing more needed to be taken into account is the altitudinal profile of backscatter (Uspensky, 1985). Due to a quick changing of the aspect angle as a function of altitude (let's consider some slant range) the largest signal will originate at the altitude where the aspect angle is close to zero but the electron density is not small. »e use here an equation for the radar effective electron density in a simplest approximation as following bottom edges of the scatter "layer" so the effective layer thickness is around 10 km (Oksman et al., 1986). Thus from Eq.4 one can find the effective electron density for each STARE radar. To formulate some quantitative description of the irregularity behaviour as a function of the E-field we will use Eq.1 in its inverse form suitable to find EDFA, ^ У ^ • For a solution we apply the effective electron densities found in accodance with Eq.4 as well as the radar parameters and the E-field azimuths derived from EXSCAT data. The method was realized earlier by Oksman et al. (1986). (6) where ,Ng ,|N|| - the electron densities at a center, on top and 21