Courant Multiplier (emult)

This is a constant factor used in calculating the spatial step size. For each radial zone, the size of the next zone is chosen to be $\Delta R= {\rm emult}/\kappa_{max}$, where $\kappa_{max}$ is the maximum photoelectric opacity. This latter quantity is calculated by a search over the spectrum, but excluding energies where the continuum optical depth to the illuminated cloud face is greater than the value of the variable taumax. The default value of emult is 0.75, and values outside the range 0.1 - 1 are unlikely to be of any practical value.