Detailed fractions of Fe¹⁶⁺ combined Fe charge states and charge-state distributions of Fe within Fe signals defined by ST_Fe, ET_Fe. (a)/(b) Fractions of Fe¹⁶⁺ and related Spearman’s rank correlation coefficient. (c)/(d) Charge state distributions of Fe. (e)/(f) Summed fraction of Fe⁸⁺ and Fe⁹⁺ compared to the summed fraction of Fe¹¹⁺, Fe¹²⁺, and Fe¹³⁺. The black dashed line is a linear fit for non-ICME cases. (g) Two-dimensional distribution of the two summed fractions in panel e/f for solar wind in 2001. The bin size is 0.02 in each direction.