Estimation of the Propagation Time of the Solar Wind Pressure Pulse between a Shock Wave and the Magnetopause Based on Simultaneous Satellite and Ground-Based Observations

Abstract

The propagation of solar wind inhomogeneities through the transition region between the bow shock front and the daytime magnetopause is an important link in the chain of solar-terrestrial connections. We analyzed a unique situation when two THEMIS satellites were near the bow shock during the solar wind pressure pulse, and the favorable location of the ground-based magnetometric equipment made it possible to determine the time of the solar wind impact on the magnetopause with greater accuracy than it was done previously. Based on the measurements, the propagation time of sudden impulse (SI) in the magnetosheath was estimated. The obtained value (~1 min) agrees with model calculations, but turns out to be 2–3 times less than that previously obtained by other authors also from satellite and ground-based observations. The propagation velocity of the solar wind in the magnetosheath (~280 km/s), the displacement velocity of the bow shock front to the Earth (~80 km/s), and the thickness of the magnetosheath at the location of the satellites (2.6–3.9RE) are determined.