Histogram of macro-particles with respect to B_eq/B_dyn to further study the effect of STA on the macro-particle population. The histograms are normalized and then scaled with the maximum value. Top panel: histograms for three different cases at four different times (color-coded, see inset at right). The top left, middle, and right panels show the histogram for cases (a), (b), and (c), respectively. Bottom panel: two-dimensional histograms showing τ_t vs. B_eq/B_dyn at the final time t = 117 Myr for three cases. The bottom left, middle, and right panels show the histogram for cases (a), (b), and (c), respectively. The color bar at the bottom panel shows the number of macro-particles.