Modulation of the solar wind velocity and density by Mercury

To study the variations in the solar wind velocity during inferior conjunctions of Mercury and Earth, we analyzed 54 events in the period 1995–2012 by the superimposed epoch method. We have found a noticeable increase in the velocity both before and after the conjunctions as well as decrease in the velocity within 3–4 days after them (Mercury׳s “shadow”). Variations of the solar wind density in 1997–2013 show a similar character, but their dispersion is substantially larger than for the velocity. The results obtained might be used to analyze variations and to improve a forecast of the solar wind velocity and density.