The effect of magnetosheath plasma flow on flux transfer events produced by the onset of merging at a single X line

Abstract

We present predictions on the signatures of flux transfer events (FTEs) at the dayside magnetopause by the single X line MHD model based on the subsolar environment: initially in the magnetosheath with background flow northward parallel to the dayside magnetopause. In conformity with our previous investigation [ Ku and Sibeck , 1997] we choose realistic parameteres for the simulation with the ratio of ρ msh /ρ sph =10, B msh / B sph = 0.5, and T msh / T sph = 0.175 along the magnetosheath and magnetospheric sides. The localized resistivity turns on near the low northern latitude of dayside magnetopause, and the initial magnitude of background magnetosheath plasma flow is set , or equivalent to 30% of magnetosheath Alfvén velocity. Simulation results produce signatures of FTEs similar to the previous case without the background magnetosheath flow [ Ku and Sibeck , 1997] but different in some respects. Events moving opposite to this flow slow down but intensify, whereas events moving in the direction of the magnetosheath flow accelerate but weaken. Similarly, the satellite observes no significant signatures of FTEs in the magnetosphere. All the FTEs exhibit asymmetric bipolar magnetic field signatures normal to the magnetopause. Scatterplots versus the plasma density reveal that steep changes for the temperature kT , the magnetic field B z , and the Alfvén velocity occur in the magnetospheric side immediately adjacent to the magnetopause.