Prolonged Magnetopause Recovery From the Impact of a Strong Stream Interaction Region

High solar wind dynamic pressure, particularly during stream interaction regions (SIRs), can strongly compress the Earth's magnetosphere, posing a risk to space-based technologies critical to modern society. This study investigates the response of the low-latitude magnetopause to an extreme SIR on 14 March 2016, using in situ observations. The magnetopause was compressed inward to near geosynchronous orbit and remained compressed for several hours after the SIR's passage, revealing an unusually prolonged recovery phase. We present three lines of analyses: (a) multi-spacecraft observations of magnetopause crossings; (b) magnetic pressure measurements inside the magnetopause; and (c) ground-based records of low-latitude geomagnetic field perturbations. The extended recovery challenges the conventional view that the magnetosphere rebounds within minutes after solar wind compression. These findings highlight the complexity of magnetospheric dynamics under extreme conditions and the need for further investigation into these regions, in order to improve space weather forecasts and protect critical technologies.