Manning parameter
= Manning parameter
{c}
{title2=$\eta=\lambda\ell_B/q$}
The dimensionless line-charge coupling $\eta=\lambda\ell_B/q$, with negative cylinder line charge $-\lambda$ and <counterions> of charge $q>0$. Here the <Bjerrum length> uses the same reference charge $q$. The mean-field infinite-dilution threshold is $\eta=1$. If $\ell_B$ is instead tabulated for elementary charge $e$ and <counterions> have charge $ze$, the corresponding coupling is $z\lambda\ell_B/e$.