Earth Planets Space, Vol. 65 (No. 10), pp. 1175-1184, 2013
E. Hadamcik1, J.-B. Renard2, A. Mahjoub1, T. Gautier1, N. Carrasco1, G. Cernogora1, and C. Szopa1
1UPMC (U. P. & M. Curie, Sorbonne Universités), Université Versailles St-Quentin, CNRS/INSU, LATMOS-IPSL, Paris, France
2LPC2E, CNRS, Orléans, France
(Received October 31, 2012; Revised May 24, 2013; Accepted May 30, 2013; Online published October 24, 2013)
Analogs of Titan's aerosols are produced in the
laboratory as grains in a gas mixture, or as layers on a
substrate. This production procedure enables the
methane-nitrogen mixture composition to be changed. The aim of this paper is to
understand the variations observed on the linear polarization of
the scattered light as a function of the production conditions.
The influence of the concentration of methane injected in the
plasma will be discussed and compared with the previous work of
Hadamcik et al.
(2009a). The diameter of the grains are measured by SEM-FEG images.
The decrease of absorption with increasing wavelength, measured by
spectroscopic ellipsometry on layers, is observed for a decreasing
initial methane ratio and analyzed in terms of an increasing `amine'
content in the materials. The phase function parameters of the
linear polarization of the scattered light are discussed in terms
of the diameters of the aggregates and of the constituent grains, and
the variation of the refractive indices (mainly absorption). The
polarization is found to be highly correlated with the constituent
grain size. Finally, the experimental results are compared to
polarization measurements from space of the Titan's atmosphere.
Key words: Light scattering, polarization, refractive indices, tholins, Titan, aerosol.