Abstract
A spacecraft configuration with two monitors near L1 and a fleet of the spacecraft orbiting in front of the bow shock brings a great opportunity to test the propagation techniques for the solar wind and the assumption on a negligible solar wind parameter evolution. We use multi-point observations of the THEMIS-ARTEMIS mission and compare them with data from the Wind solar wind monitor in order to estimate different factors influencing solar wind speed evolution.
We have found a significant deceleration (up to 6%) of the solar wind close to the bow shock and the effect extends up to 30 RE from the Earth. It is controlled by the level of magnetic field fluctuations and by the flux of reflected and accelerated particles.
We can conclude that the reflected particles not only excite waves of large amplitudes but also modify mean values of the solar wind speed measured in an unperturbed solar wind.