Plasma parameter (source code)

= Plasma parameter
{title2=$N_D=\frac{4\pi}{3}n_e\lambda_D^3$}
{wiki}

The number of electrons in a <Debye sphere>, here $N_D=(4\pi/3)n_e\lambda_D^3$. A large value characterizes weak fluctuations and weak coupling in the ordinary collective-screening regime.