Light scattering by feldspar particles: Comparison of model agglomerate debris particles with laboratory samples

We present comparisons of the non-zero light-scattering Mueller-matrix elements of agglomerated debris particles with those of well-characterized experimentally measured feldspar samples at blue and red wavelengths. The only completely free parameter in our comparisons is the small-size cut-off of the sample, which was not known. The significance is that both the light scattering and the measured properties of model and real particles agree very well. While some tweaking of the particle parameters could achieve some improvement, the fits are remarkably good, with significant deviations (∼5%) occurring in portions of the polarization elements, e.g. S34. We suggest that the reason for the good fits is not that the model particles exactly represent those of the sample particles, but rather that both sets of particles belong to a class of highly irregular particles, whose high degree of irregularity dominates the resulting scattering behavior, suppressing the effect of any characteristic morphological features.