Solar wind control of the magnetopause shape, location, and motion

The authors have assembled a data set of 1,821 magnetopause crossings. Separate fits to subsets of this data set determine the magnetopause location as a function of solar wind dynamic pressure and interplanetary magnetic field operation. Solar wind dynamic pressure variations produce self-similar magnetopause motion on time scales of one hour or longer. They verify the pressure balance relationship between the solar wind dynamic pressure and the location of the subsolar magnetopause. They quantify the relationship between the IMF Bz, region 1 Birkeland current strength, the position of the subsolar magnetopause, and the shape of the dayside magnetosphere. Cross sections of the dayside magnetopause in planes perpendicular to the Earth-Sun line are oblate