Physics of auroral phenomena : proceedings of the 34th Annual seminar, Apatity, 01 - 04 March, 2011 / [ed.: A. G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2011. - 231 с. : ил.

T.A. Kornilova, I.A. Kornilov features are northern structures in the TV camera field of view, breakup in the south boundary of the auroral oval, southward motion of the northern structures before and after breakup onset at the south and their subsequent passing through the southern breakup after the contact of counter-streaming structures. During event of 17.02.2002 this effect is observed both during pseudobreakup at 20.17 UT and the following substorm, which began at 20.23 UT. During the second event on 26.03.1998, breakup arose in the region of diffuse pulsating prebreakup arc. The third event on 09.02.1997 was connected with strong and prolonged magnetic disturbances. Substorm onset took place more to the south than those in Fig. 2 a,b. 19.40 21.00 UT Fig-1 Standard N-S keogram (a), filtered keogram (b) and the same filtered keogram, but with the weak structures enhanced by white lines (c), H-components from LYR, SOR, LOZ and OUJ (d). The horizontal bar in Fig. Id marked “TV” indicates time interval of keograms in Fig.la-c. The arrows point to the aurora activation onsets seen in the northern and southern regions of the keograms. 3. Discussion An analysis of TV auroral records and filtered and standard keograms for the period of 1998-2010 years show that weak but quite visible traces of northern structures penetrating through the active spreading northward auroral forms of the southern breakup are not extremely rare phenomenon. Apparently, it is seen every time when counter­ streaming structures of northern and southern activations come into visible contact. However, it is very difficult to register this phenomenon as it is masked by complete dynamics of bright and fast moving breakup auroras. It is practically impossible to reveal this effect on the individual TV frames. It could be detected statistically and seen only in filtered keograms. Some authors, for example, [Lyons et al., 1999; Kauristie et al., 2003 and ref. therein] consider the polar boundary intensifications (PBIs) as a result of the magnetotail magnetic reconnections, which generate the bursty bulk flows (BBFs) manifested in the ionosphere as auroral streamers drifting from the polar boundary to the equator. 10