Ionospheric conductivity dependence of dayside region-0, 1, and 2 field-aligned current systems: statistical study with DMSP-F7

摘要

The present study statistically examines the dependence of the intensitiesof dayside (MLT=8-12h) large-scale field-aligned currents (FACs) on theionospheric conductance using the summary data of DMSP-F7 constructed by theprocedure of Higuchi and Ohtani (2000). We have found that, in thedayside region, R1 and R0 have a higher correlation between ionosphericconductivity and FAC intensity than R2, suggesting that R0 and R1 are drivenby a more voltage-like source than R2. This result is consistent with theidea that R1 and R0 are driven by the interaction between the solar wind andthe open magnetospheric magnetic field. We have also found that dayside FACintensities are latitudinally well balanced when they have a three sheetstructure (R0, R1 and R2); on the other hand, for a two sheet structure (R1and R2), the intensity of R1 is larger than that of R2, so that the netcurrent has the polarity of R1.