Nonlinear counterion accumulation in planar screening
= Nonlinear counterion accumulation in planar screening
A strong negative surface potential creates exponentially enhanced positive <counterion> <density> and exponentially suppressed negative <co-ion> <density>. The <co-ion> population remains positive, unlike an extrapolated linear approximation. Finite ion size and <correlations> eventually limit the applicability of point-ion <mean-field theory>.