J W Hovenier

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We have measured the scattering matrix as a function of the scattering angle of randomly oriented particles of a Mg-rich olivine sample and a ground piece of Allende meteorite as cometary analogues using lasers at two wavelengths (442 nm and 633 nm). The elements of the scattering matrix, F ij , depend on the scattering angle, the wavelength of the laser(More)
We discuss the composition and size distribution of the dust in the coma of comet Hale-Bopp. We do this using a model fit for the infrared emission measured by the infrared space observatory (ISO) and the measured degree of linear polarization of scattered light at various phase angles and wavelengths. The effects of particle shape on the modeled optical(More)
[1] We present measurements of the whole scattering matrix as a function of the scattering angle at a wavelength of 632.8 nm in the scattering angle range 3°–174° of randomly oriented particles taken from seven samples of volcanic ashes corresponding to four different volcanic eruptions: The samples were collected at different distances from the vent. The(More)
The structure of matrices that represent a linear transformation of the Stokes parameters of a beam of light into the Stokes parameters of another beam of light is investigated by means of the so-called Stokes criterion. This holds that the degree of polarization of a beam of light can never be changed into a number larger than unity. Several general(More)
Retrieval of biogeochemical parameters from remotely sensed data in optically complex waters such as those found in coastal zones is a challenging task due to the effects of various water constituents (biogenic, nonalgal and inorganic particles, dissolved matter) on the radiation exiting the ocean. Since scattering by molecules, aerosols, hydrosols and(More)
The pseudo-spectral time domain (PSTD) and the discrete dipole approximation (DDA) are two popular and robust methods for the numerical simulation of dielectric particle light scattering. The present study compares the numerical performances of the two methods in the computation of the single-scattering properties of homogeneous dielectric spheres and(More)
In this paper we study the combined effects of size and shape of small solid state particles on the absorption, emission and scattering characteristics. We use the statistical approach to calculate these optical properties. In this approach the average optical properties of an ensemble of particles in random orientation are represented by the average(More)
We model the 10 µm absorption spectra of nonspherical particles composed of amorphous silicate. We consider two classes of particles, compact ones and fractal aggregates composed of homogeneous spheres. For the compact particles we consider Gaussian random spheres with various degrees of non-sphericity. For the fractal aggregates we compute the absorption(More)
We present measurements of ratios of elements of the scattering matrix of Martian analogue palagonite particles for scattering angles ranging from 3 • to 174 • and a wavelength of 632.8 nm. To facilitate the use of these measurements in radiative transfer calculations we have devised a method that enables us to obtain, from these measurements, a normalized(More)
  • C J Braak, J F De Haan, C V M Van Der Mee, J W Hovenier, L D Travis
  • 2001
Parameterized matrices are discussed that may be used as (single) scattering matrices for interpretations of the brightness and polarization of planetary atmospheres containing randomly oriented small particles. A number of guidelines are developed for the construction of such matrices. These guidelines are based on (i) physical conditions for the elements(More)