Studies of the solar wind-magnetosphere interaction often rely on L1 observations that are propagated toward the Earth. The propagation techniques are based on an assumption of a negligible evolution of upstream parameters along the solar wind path.
The data measured in the L1 point by ACE are propagated and compared with observations of the THEMIS spacecraft orbiting in the near-Earth space. A special attention is paid to the region in front of the Earth’s bow shock (foreshock).