Physics of auroral phenomena : proceedings of the 38th annual seminar, Apatity, 2-6 march, 2015 / [ed. board: A. G. Yahnin, N. V. Semenova]. - Апатиты : Издательство Кольского научного центра РАН, 2015. - 189 с. : ил., табл.

Field-aligned current dynamics in two selected intervals [R0+ and R0-] are connected in parallel to this pair. The ionospheric current from the R1+ FAC cell flows into the R2- and R0- FAC cells, and flows down along field lines into the DRP1 partial ring current. Further, the current flows from DRP1 into the 0 3 :1 5 ionosphere of both hemispheres and closes onto the Г generator through the Rl-and rl-cells. The letter r replaces the letter R in the Southern Hemisphere. Now, we switch to the IRN± intensity plots in each of the RN± cells in the Northern Hemisphere. Fig. 3 presents the plots from the data on the 2000 April 6 (02-04) UT interval. The plots are grouped by the Kirchhoff Rule 1. In the Northern Hemisphere, the following equations correspond to this rule I r .+ = ( I r 2-) + ( I ro -) (1 ) I r i - = (I r 2+) + ( I ro +) (2 ) Here, Equations (1) and (2) are for the postmidnight («dawn») and premidnight sector (“dusk”) of the MLT nightside half. In the Southern Hemisphere, the same equations, but with the letter r instead of the letter R are true. The cell boundary was determined in one of the Rl nightside sectors, the boundaries of the corresponding nightside cells in R2 and R0 were determined through fitting based on Equations (1), (2) (within (10-20) %). Further, there follow the technique applications. Now, we analyze the FAC behavior during two intervals of the 6 April 2000 superstorm. Fig. 5 (Appendix) provides the variations in the SW parameters and AE indices. 3. Events 1, (02-03) UT interval Fig. 3 presents the first maximum of AE index at 0255 UT, and, simultaneously, the FAC intensity maximum in the R1-, R2+ cells of the dusk sector. In contrast, the minimum of the IR]+, Ir 2 . values is observed at the same time in the dawn sector. Such a FAC distribution corresponds to the EP summer-type FAC in the Northern Hemisphere [Mishin et al., 2015a]. 4. Events 2, (03-04) UT interval Fig. 3 also presents the AE index second maximum at 0335 UT, and, simultaneously, the FAC intensity maximum in R1+ and R2- cells of the dawn sector. In contrast, one observes the IRi_and Ir 2 +minimum in the dusk sector at the same time. Such a FAC distribution corresponds to the EP winter-type FAC in the Northern Hemisphere [Mishin et al., 2015b]. Figure 1. Examples of the FAC density distribution maps: downward (dotted lines) and upward (solid lines) currents. Thick lines are the boundaries of the I-P Regions. Filling shows the highlighted mesoscale cells. We show the boundaries of three I-P Regions [Mishin et al, 2011], as well as the boundaries of mesoscale cells within every Region. The symbols of cells R0±, Rl±, R2± (0,1,2 is the 1-P Region number, the +(-) sign corresponds to the downward (upward) FAC) are shown for the nightside interval ~ (1806) UT: it is this interval that is investigated in this paper. There is a local FAC maximum within each cell. dusk dawn * 0 - Figure 2. Scheme of the M-I system electric circuit for two hemispheres. Explanations are provided in the text. 5. Events 3, (12-15) UT interval In Fig. 4, one can see the AE index first maximum at 1330 UT, and, simultaneously, the FAC intensity maximum in the R1-, R2+ cells of the dusk sector. In contrast, one observes low values of IRi+, 1^. in the dawn sector at the same time. Such a FAC distribution corresponds to the EP summer-tvpe FAC in the Northern Hemisphere [Mishin et al., 2015a], 6. Discussion and Conclusions We addressed three intervals with signatures of separate expansion phases (EPs) during the 2000 April 6 25