Структура и динамика полярных токовых систем : материалы международного симпозиума «Полярные геомагнитные явления», 25-31 мая, Суздаль, СССР / Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т. – Апатиты : [б. и.], 1988.

electrojet, that it grows only insignificantly during the activity enhancement or can even disappear completely during the active phase during which the westward electrojet reaches a high intensity (see e.g. Grai’e 1969, Troshichev and Feldstein 1970, Mishin and Popov 1971, Iijima and Nagata 1972, Grafe 1976, Mishin 1977). This resul-t has been laid down by Troshichev et al./1974/ in the designations DP 12 for the "growth phase variation" and DP 11 for the "explosion phase variation". The opinion expressed by Akasofu et al./1965/ that the eastward eleotro- jet in the afternoon sector is only the return current of the westward electro jet flowing poleward in the evening sector does not agree with this result. Rostoker and Kisabeth /1973/ believe that the eastward electrojet grows simul taneously with the westward electrojet and that it is only a special phenomenon of the growth phase. However, in their opinion too, a part of the eastward electrojet shall be return current of the westward electrojet. These different opinions on the occurrence of the eastward electrojet expressed in many publications of the last 10 to 20 years show that there was no clearness on the nature of the eastward electrojet. And what about today? It should be mentioned that Baumjohann et al. /1980/ speak in one paper of a "substorm-intensified eastward electrojet". What is meant with "substorm intensified eastward electrojet"? Is in this case during the substorm the convection enhanced only or is there another process which intensifies the eastward electrojet? Pig. 1.Conception about convection and substorm electrojets after Baumjohann /1982, The idea on the nature of the auroral electrojets valid at present contains two possible processes of the generation of auroral electrojets, the convection electrojet (two vortex DP 2 current system) generated by large- scale convection as a consequence of energy feeding of the interplanetary space, and the substorm electrojet (one vortex DP 1 current system) caused by unloading processes occurring in the magnetospheric tail. Pig.1 shows this idea according to Baumjohann /1982/ in a quite clear sketch. According to this, the eastward electrbjet is only the effect of large-scale magnetospheric convection and not an element of the substorm process. A westward electrojet, however, is produced by both processes. Kamide and Vickrey /1903/ complete this picture (your Pig.6) showing that in the evening and in the late morning sector especially the electric field is drive- effective for eastward and westward convection electrojet and that in the midnight sector the Hall conductivity (particle precipitation) generates the westward aubstorra electro jet. In its simplicity this picture is very impressing and convincing. In spite of this it must be asked whether this picture is not, after all, too simple. Is the development of the eastward electrojet really so that it fits 58