Graphical representation of the conversion between grown and small dust shown for the case of $a_{\max }^{n+1}>a_{\max }^n$ The solid blue and orange lines indicate the dust distribution at the current time step n. The next time step n + 1 is denoted by the green dashed line. Three cases are presented in the three panels from left to right: (i) the case with a continuous distribution at a_⋆ ; (ii) discontinuous distribution with a dominance of grown dust turning into a continuous distribution, (iii) redistribution of the excess of small dust to provide a continuous distribution.