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.

convection. 4. During maximum current development intensifications succeed, one another (in 5 min average) and greatly expand over the latitudes. This period reflects large-scale changes during current disruption in the magnetospheric plasma sheet forming an intense current wedge. Connection between maximum auroral expansion and disturbance in the magnetic field D-component on the ground is of prominent importance for diagnostics of magnetospheric disturbances. R E F E R E N C E S : 1. Mishin V.M. Geomagn.and Aeronomy, 1978, 2§, 961. 2. Arnoldy R.L., Moore T.E. J.Geophys.Res., 1983, 88, 6213. 3. Baumjohann V/., Pellinen R . , Opgenoorth H.J., Nielsen E. Planet. Space Sci., 1981, 2£, 431. 4. Lazutin L.L., Baumjohann W . , Glassmeier K.-H. et al. XXV COSPAR, Abstracts, Graz, Austria, 1984, 163. 5. Lezniak T.W., W i n d e r J.R. J.Geophys.Res., 1970, 75, 7075. P.F.Bythrow, M.A.Doyle, T.A.Potemra, L.J.Zanetti, R.E.Huffman, C.I.Meng, D.A.Hardy, F.J.Rlch, R.A.Heelis MULTIPLE AURORAL ARCS AND BIRKELAND CURRENTS: EVIDENCE FOR PLASMA SHEET BOUNDARY WAVES ABSTRACT. Quasi-periodic structures of small-scale Birkeland currents, energetic electrons, ion drifts and auroral forms in the dawn sector have been observed simultaneously with the HILAT spacecraft. These structures map to the Low Latitude Boundary Layer using a model geomagnetic field. This mapping ia supported by the observed characteristics of the energetic elect rons and the relationship between precipitating electrons, Region 1 Birkeland currents and plasma drift. The spacing of the Birkeland currents, their location with respect to ionospheric electron populations and their relation ship to the observed auroral forms are interpreted as the result of quasi- periodic variations of the Low Latitude Boundary Layer. Valuea of potential, estimated from assumed characteristics of a large-scale wave propagating in this layer, agree with those determined from the HILAT particle and drift measurements. These results support the view that the wave propagation at the Low Latitude Boundary Layer Plasma Sheet interface can be a source of multiple auroral forms at low latitudes. We suggest that the Kelvin-Helmholtz instability may be the ultimate source of these waves. 47