Three-dimensional Global Hybrid Simulations of Flux Transfer Event Showers at Mercury

Abstract

One of the important MESSENGER observations is the formation of flux transfer event (FTE) showers, where tens of FTEs are observed in a short time interval of about 1–2 minutes, at Mercury’s magnetopause. In this paper, we investigate the interactions between the solar wind and Mercury’s magnetosphere using three-dimensional global hybrid simulations. When the interplanetary magnetic field (IMF) is purely southward, we can observe FTE showers at the low-latitude dayside magnetopause, and these FTEs can propagate northward or southward with a speed of about 90 km s−1. When the IMF is purely northward, FTE showers can be produced in both the northward and southward hemispheres of the high-latitude nightside magnetopause, and these FTEs propagate toward the magnetotail with a speed of about 250 km s−1. The typical FTEs have a duration of 1–2 s, and reoccur in 5–6 s. Our simulations provide a good explanation for FTE showers observed by MESSENGER.