In our statistical study of the solar wind propagation from L1 to the Earth's bow shock, we use multi-point observations from the THEMIS-ARTEMIS mission and compare them with a WIND solar wind monitor with motivation to estimate different factors influencing evolution of solar wind speed. We have found a systematic deceleration of the average solar wind with a decreasing distance to the bow shock that 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 quantities measured in an unperturbed solar wind.