Detailed dayside auroral morphology as a function of local time for southeast IMF orientation: implications for solar wind-magnetosphere coupling

摘要

In two case studies we elaborateon spatial and temporal structures of the daysideaurora within 08:00-16:00 magnetic local time(MLT) and discuss the relationship of this structure tosolar wind-magnetosphere interconnection topologyand the different stages of evolution of open field lines in the Dungeyconvection cycle. The detailed 2-Dauroral morphology is obtained from continuous ground observationsat Ny Ålesund(76° magnetic latitude (MLAT)), Svalbard during two days when theinterplanetary magnetic field (IMF) is directed southeast(B_yz<0). The auroral activityconsists of the successive activations of the following forms:(i) latitudinally separated,sunward moving, arcs/bands of dayside boundary plasma sheet (BPS) origin,in the prenoon (08:00-11:00 MLT) and postnoon (12:00-16:00 MLT)sectors, within 70-75° MLAT,(ii) poleward moving auroral forms (PMAFs) emanating fromthe pre- and postnoon brightening events,and (iii) a specific activity appearing in the07:00-10:00 MLT/75-80° MLATduring the prevailing IMF B_y