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
where emult is defined below, and
is the maximum opacity from the
previous step calculation.
is only calculated from energies where
the optical depth to the illuminated face of the cloud is less than taumax, where
taumax is defined below. The default value for nsteps is 2.
The default value of emult is 0.5, and values outside the range 0.1 - 1 are
unlikely to be of any practical value.