The Momentum Transferred into the Magnetosheath by a Dust Cloud

Abstract:

Early in 2018, an hour-long structure was observed by eight spacecraft in the solar wind, and then by four spacecraft in the magnetosheath after being compressed. The structure featured a gradual enhancement in the magnitude of IMF, as well as a thin current sheet in the center, both of which have been seen numerous times in interplanetary space. This structure is interpreted as a magnetic field perturbation around a charged dust cloud traveling with the solar wind. Studies of cases with fewer observations have found that such structures approach the magnetosphere about ten times per year. The momentum carried by the dust cloud does not completely dissipate upon penetrating the bow shock. They are then transferred to the ambient solar wind in a significant amount. Momentum transfer with such significant energy dumped into the magnetosheath is worth studying further. Based on our analysis of the plasma and field data, we use a global multi-fluid MHD model to reproduce this process, to evaluate the momentum and energy transfer, and to determine the associated effect on the magnetosphere.