Quasi-Steady Dayside Reconnection

抄録

I describe the promising recent developments and important remaining questions concerning quasi-steady reconnection (QSR) at the dayside magnetopause, Research on this topic remains buoyant although there is now little doubt that QSR supplies a significant fraction of the mass and the overwhelming amount of the momentum involved in magnetospheric motion. The new developments include the use of ground and low-altitude observations, especially Birkeland current patterns and plasma flows, to monitor the large-scale characteristics of QSR, the recognition that magnetospheric energetic particles may remain trapped on dayside reconnected field lines, and the possibility that the velocity shear accompanying QSR may drive the magnetopause current layer Kelvin-Helmholtz unstable. Among the key remaining questions are: what, besides large magnetic shear, are the necessary conditions for QSR to occur; how can the diffusion region be identified; and what is the detailed structure of the reconnection layer? Finally I re-emphasise that dayside QSR and flux transfer events are closely related and may occur simultaneously.