## 6. ConclusionThe first basic assumption of this Paper is to model the solar H incident radiation on the spicule by a negative exponential profile of width Å . Due to the fact that we use a gaussian profile, the average on the shifted velocity distribution of the scatterer can be performed nearly analytically. An important result is that limb darkening enhances the polarization degree together with the fact that isotropic collisions decrease the degree itself. We show that the polarization degree is maximum in a range of anisotropic velocities compatible with the real velocity of matter in spicules. The order of the polarization degree is for
atoms situated at an altitude of km and for an
electron density of cm The theory we have built is very general and may be improved by the introduction of a weak static magnetic field. This will be done in future work. © European Southern Observatory (ESO) 1998 Online publication: April 28, 1998 |