Figure 2.

(a) The non-dimensional total charge (solid lines) profiles in the pores with different widths $H^{*}=1.5$ and $H^{*}=2.0$. The dashed lines indicate the square-root trends at early times. (b) The slit pore charging (solid lines) in the linear-log scale for $H^{*}=1.5$ and $H^{*}=2.0$. Long-dashed and short-dashed lines show two exponential trends (long-dashed and short-dashed lines) at intermediate and late times. (c) The separated total charge contributions from co-ions (red) counter-ions (blue) as function of time. In all plots $U^{*}=10$ and $\tau =L^2/D$.