Движение на восток радиоавроры и петель свечения в утреннем секторе : [науч. докл. ПГИ-79-1] / Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т ; М. В. Успенский, А. В. Кустов, Е. В. Пудовкина и др. – Препр. ПГИ-79-1. - Апатиты : [б. и.], 1979.

in Fig.5 is the effect of the method of picture building. The presence of a strong eastward electric field exceeding level can explain the appearance of the irregularities with the symmetrical loop filling. But the small north-southern size of the loop raises the question about the closing of the intensive southern Hall current being connected with the eastward electric field. Southward to the northern ars with the upward field-aligned current there would exist the branch of the downward field-aligned current. This downward current would move with the loop closing the Hall component of the ionospheric current on the bright southern arc as a branch of the upward current. The Pelcrsen current would be then flowing to the east in the leading part of the loop toward the negative charge of the precipitating electrons. The weak ness of the discussed suggestions is the lack of experimen tal data confirming the reality of this picture. At the same time in the case of a simple arc the field-aligned currents can also consist of several close upward and downward bran ches. For example it can be seen from the paper by Kamide and AkasofuT1976. The following auroral loop after 01.28:20 UT as it was noted was filled with radioaurora asymmetrically. Assume the eastward electric field of the loop exists here also but its amplitude is a little less than in the first case. Then re sultant electric field in •‘he loop as a superposition of in ternal and background fields will be south-eastern. At the same time the auroral loop moving to the east is widening on the observational meridian to poleward and equatorward. It would raise the gradients of the concentration in the inter nal parts orientied ta the east, to the north and to the south. Indeed behind the moving arc the initial high elec tron density is recombined and gradually decreased to the background level. Thus the moving arc leaves a wake train of the recombined ionization. Hear the southern arc the ьи-ath— eastward field and the gradients coincide in the direction, i.e. Just here the drift gradient instability increment Is the highest. Such increment will be the smallest near the northern arc. The necessity of the accounting of the resul— 27