Polar observations of convection with northward interplanetary magnetic field at dayside high latitudes

摘要: This study of dayside electrodynamics provides a first view quasi-dc electric fields measured by Polar at middle altitudes. Three high-latitude passes chosen for analysis, occurred while was in the midday sector and interplanetary magnetic field (IMF) maintained steady northward orientation clock angles near 40° YGSM – ZGSM plane. At different times during passes, encountered electron ion fluxes from central plasma sheet (CPS), boundary sheet, polar rain, various magnetospheric regions. Although within layers were highly variable, we derived average components convection. The results compare favorably with convection characteristics four-cell patterns observed ionospheric altitudes IMF. We show that lobe cells both positive negative polarity early postnoon sector. potential extends well into prenoon Inverse, energy-dispersed He++ detected regions sunward Sunward extended region rain north merging line's projection. signatures indicate process is time varying patchy. Particle measurements are consistent afternoon, auroral cell closing low-latitude layer, which extend many tens RE tailward dusk terminator. Taken larger context, provide new insight concerning evolution distorted two-cell large IMF to four low angles.