Average variations with fraction of year, F. The data are for 1995–2019, inclusive and are binned into 36 equal width bins of F (each just over 10 days in length) and a 3-point boxcar running mean applied. The data are then normalised by dividing by the mean for all samples. (a) Shows the normalised variation in power input into the magnetosphere, P _α (red line); the solar wind dynamic pressure, p _sw (blue line) and the am index (black line). (b) The variations of the component terms in p _sw (which is again shown by the blue line): the mean solar wind ion mass, m _sw (orange line); the solar wind number density, N _sw (green line) and the square of the solar wind speed, V _sw ² (mauve line). The black dashed line is the inverse square of the Sun-Earth distance, . The vertical dot-dash lines mark the equinoxes.