Formation of external magnetic enhancements above crustal anomalies. The schematic illustration shows how velocity shear at a lunar minimagnetosphere drives the KHI. A cluster of magnetic anomalies (blue) deflects the incident solar wind (orange arrows). In panel (a), under slow solar-wind conditions, classical vortex structures develop along the boundary, producing either oscillatory EMEs similar to those observed at Earth’s magnetopause or markedly intensified EMEs, as illustrated in the white inset. In panel (b), higher solar-wind speeds lead to steepening surface waves that generate fast-mode shocks (green curves), producing sharp, shock-like EMEs (white inset) observed above the surface. This schematic illustrates the physical interpretation inferred from the observations and supported by the simulations presented below.