Chandrasekhar number
= Chandrasekhar number
{c}
{title2=$Q=B_0^2d^2/(\mu_0\rho_0\eta\nu)$}
For an imposed field $B_0$ in a layer of depth $d$, the <Chandrasekhar number> compares magnetic tension with viscous and magnetic-diffusive effects. Here $\eta$ is <magnetic diffusivity> and $\nu$ is <kinematic viscosity>. In thermal-diffusion units the linear magnetic-force coefficient is $Q\zeta$, where $\zeta=\eta/\kappa$ and $\kappa$ is <thermal diffusivity>.