Evolution of the temperature anisotropy and temperature ratio of α particles and protons with Coulomb collisional age A_C(α, p). Temperature anisotropy of protons and α particles are shown in the top two rows, and T_α/T_p are shown in the bottom row. The two black arrows in panels (b) and (d) indicate the trends of A_Tp and A_Tα with A_C(α, p) within 20 R_⊙, respectively. The color bar indicates the heliocentric distance. The black contour denotes the counts of intervals in one bin equaling 10.