Jupiter: A fundamentally different magnetospheric interaction with the solar wind

Magnetic reconnection between the solar wind and Earth's magnetic field creates an "open" magnetosphere with erosion of magnetic flux from the dayside and return on the nightside. At Jupiter, the large source of plasma from Io and fast rotation rate create a magnetosphere whose dynamics is dominated by internal processes. This, along with its sheer physical size, makes the nightside return of flux difficult, if not impossible. However, because magnetic reconnection still occurs on Jupiter's dayside magnetopause, it has been generally assumed that Jupiter's magnetosphere must be similarly open. Here we show how additional reconnection between the IMF and open magnetospheric flux back near flanks can re-close this open flux without having to invoke reconnection in the Jovian magnetotail. Our reconnection cycle solves the problem of closing and returning open magnetic flux in a large, internally dominated magnetosphere that constantly sheds large amounts of plasma down its magnetotail.