title: Backscattering and negative polarization of agglomerate particles.
abstract: We used the discrete dipole approximation to study the backscattering of agglomerate particles consisting of oblong monomers. We varied the aspect ratio of the monomers from approximately 1 (sphere) to 4, while we kept the total particle volume equivalent to that of an x = 10 sphere for m = 1.59 + i0 and 1.50 + i0 and considered two values of agglomerate packing density: rho = 0.25 and rho = 0.1. We found that these particles do not display a prominent brightness opposition effect but do produce significant negative polarization over a range of near-backscattering angles. Increasing the monomers' aspect ratio can make the negative polarization much more prominent. We have noted also that decreasing m and p can reduce the amplitude of the negative polarization for these particles.
authors.affiliation: Institute of Astronomy, Kharkov National University, 35 Sumskaya Street, Kharkov 61022, Ukraine.
authors.forename: Evgenij
authors.initials: E
authors.lastname: Zubko
authors.forename: Yuriy
authors.initials: Y
authors.lastname: Shkuratov
authors.forename: Matthew
authors.initials: M
authors.lastname: Hart
authors.forename: Jay
authors.initials: J
authors.lastname: Eversole
authors.forename: Gorden
authors.initials: G
authors.lastname: Videen