Hot star polarimetric variability and the nature of wind inhomogeneities

The problem is addressed of how much hot star polarisation variability can result from density redistribution processes within the wind as opposed to localised enhancement of stellar mass loss rate, such as ejections of wind inhomogeneities. For optically thin electron scattering, we present a theor y for the relative polarisation arising from particle redistribution and co nsider several specific cases relevant to interpreting observations of wind variability. It is concluded that, allowing for partial cancellation of th e contribution from compressed and evacuated regions, density redistributio n internal to the wind can produce significant polarisation but only for pr ocesses that redistribute wind material over relatively large radial or ang ular scales. This conclusion favors extended spatial structures (e.g., from strong radiatively driven shocks) over localised condensations (e.g., from radiative instabilities).