Clumping, or random density inhomogeneities
Creates a porous wind, potentially with paths having
lower column densities (but other paths higher, if mass is
conserved)
Can reduce average optical depth of the wind
appreciably only if individual clumps are optically thick: Then the atomic
cross section in the opacity is replaced by the physical
cross section of the clump
Clumps would therefore have to be
quite large
Non-isotropic clumping can have an
effect on line profilesÉ