Plasma sheet magnetic fields and flows during steady magnetospheric convection events

摘要

Inner magnetosphere magnetic field and plasma flow data are examined during 228 steady magnetospheric convection events. We find that the BZ component of the magnetic field around geostationary orbit is weaker than during average conditions and the plasma flow speeds are higher than average in the dusk sector just beyond geostationary orbit. The steady magnetospheric convection periods include more enhanced earthward and tailward flow intervals than during average conditions. The steady convection period magnetic field is not steady: The near-geostationary nightside field grows increasingly taillike throughout the steady convection period. In the midtail, earthward flows are enhanced in a wide region around the midnight sector, which leads to enhanced magnetic flux transport toward the Earth during the steady convection periods. Compared to well-known characteristics during magnetospheric substorms, the inner tail evolution resembles that during the substorm growth phase, while the midtail flow characteristics during steady convection periods are similar to those found during substorm recovery phases.