Dependence of O_R on solar wind speed (V_SW). Panel (a): Scatter plot of O_R vs. V_SW using a 2-day sliding window (1-hour cadence), with overplotted averages and standard errors for solar maximum (red; 24 months before to 6 months after solar maxima in 2001-11-01, 2014-04-01, and 2024-08-01), solar minimum (blue; same window around solar minima in 1996-08-01, 2008-12-01, and 2019-12-01), as well as for the intermediate ascending and descending phases (light cyan and light lime). Panel (b): Conditional probability distributions of O_R for different V_SW ranges. The smoothing curve was fitted exclusively to the primary, contiguous high-density region (probability density > 0.02), whose outline is indicated by the white or gray contour in the figure. Minor, isolated regions were excluded from the fit.