FN_KAPPA

FN_KAPPA = <Quantity 4.62581807e+10 erg / (K cm s)>

Thermal conductivity normalization for MAS.

The Spitzer parallel conductivity \(\kappa = \kappa_0 T^{5/2}\) (with FKSPITZ = \(\kappa_0\)) has unit of erg cm⁻¹ s⁻¹ K⁻¹. In MAS code unit the dimensionless conductivity \(\kappa_\text{code}\) satisfies

\[\kappa_\text{phys} = \kappa_\text{code} \times \frac{k_B\,n_0\,L_0^2}{T_0}.\]

The dimensionless Spitzer coefficient stored in the code is therefore

\[F_\kappa^\text{code} = \kappa_0 \frac{T_0^{5/2}}{k_B\,n_0\,L_0^2/T_0\cdot T_0^{5/2}} = \frac{\kappa_0\,T_0^{5/2}}{F_\kappa}.\]