Electron-Only Reconnection as a Transition Phase From Quiet Magnetotail Current Sheets to Traditional Magnetotail Reconnection

摘要

In Earth's magnetotail, we report three types of current sheets: Quiet current sheets supported by antiparallel lobe fields, “electron-only” reconnecting current sheets, and traditionally reconnecting current sheets. We survey Earth's magnetotail for each current sheet type and perform event studies on one of each. One quiet current sheet, three electron-only reconnecting current sheets, and one traditionally reconnecting current sheet are placed in order to showcase the possible time-evolution of reconnection onset. Over time, electron-only reconnecting current sheets increase in thickness, electron and ion outflow exhaust, perpendicular ion temperature, parallel electron temperature, and Hall electric field. These features support a transition phase from a quiet current sheet to traditional reconnection. Statistics of each current sheet type show that, during electron-only reconnection, electrons are heated and evacuate the reconnection region while ions retain the properties of a quiet current sheet. In addition, statistics of solar wind properties indicate that electron-only and traditional reconnection do not have unique solar wind drivers. Guide field statistics of electron-only reconnection imply that aspects of the driving mechanism of electron-only reconnection remain unclear.