Jupiter's polar ionospheric flows: theoretical interpretation

Prompted by recent observations of ion flows from Doppler measurements of infrared auroras, we here discuss the nature of the plasma flow in Jupiter's high-latitude ionosphere. The physical picture is based on a combination of three elements, namely an inner Hill-type sub-corotating region containing outward-diffusing iogenic plasma, an outer sub-corotating region where iogenic plasma is lost down the tail, principally in the dusk and midnight sector via the reconnection-related Vasyliunas-cycle, and finally an outermost boundary region located principally in the dawn-side magnetosphere which is associated with solar wind interaction and the Dungey-cycle. The nature of the ionospheric flow and currents resulting from the combined action of these processes is outlined. In particular, we point out that the region of open field lines associated with the Dungey-cycle should be a region of near-stagnation in the ionosphere in the rest frame of the dipole, compared with surrounding regions of few-km s[superscript −1] sub-corotational flow.