scattering

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scattering

1. the random deflections suffered by light or other electromagnetic radiation passing through an irregular medium. If the source, medium, or observer are in relative motion, scintillations – random fluctuations of amplitude – may be seen as the source is observed through the medium: scattering in the Earth's atmosphere causes the stars to twinkle. Scintillations may only be seen if both the angular size of the source and the bandwidth in which the waves are received are small enough. Otherwise, the effect of the scattering may simply be to broaden the apparent angular size of the source.

Scintillations of radio waves are observed to occur because of irregularities in the refractive index of the ionosphere, the interplanetary medium, and the interstellar medium giving ionospheric scintillation, interplanetary scintillation (IPS), and interstellar scintillation (ISS), respectively. IPS may be used in determining the angular sizes of radio sources at meter wavelengths in the range 0.1 to 2 arc seconds, or for measuring parameters of the solar wind. ISS cause some of the random fluctuations in the intensity of pulses received from pulsars.

Light may be deflected from its direction of travel by fine particles of solid, gaseous, or liquid matter. For very small particles (less than one wavelength in size) the effect results from diffraction, reflection playing a more important part with increasing size; this is known as Rayleigh scattering and is very dependent on wavelength. Very small particles scatter blue light more strongly than red light. This leads to the reddening of starlight by cosmic dust and to the reddening of the Sun when seen through a thick layer of atmospheric dust.

2. the deflection of individual particles (such as electrons or photons) from their direction of travel as a result of their interaction with other particles, nuclei, atoms, or molecules in the medium through which they are passing. There are various scattering processes including Compton scattering.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

scattering

[′skad·ə·riŋ]
(electromagnetism)
Diffusion of electromagnetic waves in a random manner by air masses in the upper atmosphere, permitting long-range reception, as in scatter propagation. Also known as radio scattering.
(physics)
The change in direction of a particle or photon because of a collision with another particle or a system.
Diffusion of acoustic or electromagnetic waves caused by inhomogeneity or anisotropy of the transmitting medium.
In general, causing a collection of entities to assume a less orderly arrangement.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Propagation of light in biological turbid tissues is a complex interplay between scattering and absorption.
Thus, a simplified analytical approach, which can facilitate processing of experimental data of light scattering processes into biotissues in realistic geometries, is of great importance.
The purpose of this paper is to develop a simplified analytical approach elucidating the physical picture of scattering processes in turbid tissues and providing interpretation of experimental results, particularly in tissues with high absorption and within a small distance (comparable to the transport length, [I.sub.t] = 1/([[mu].sub.a] + [[mu]'.sub.s])) from the source.
As increasing number of people are using ash scattering services together with Online Memorials and networking sites, blogs and Facebook, as ways of showing love and respect for the deceased.
It is now well established that an increasing pigment-filling fraction gives rise to "dependent" light scattering as a fundamental phenomenon leading to a gradual loss in the scattering efficiency.
In particular, it appears that a series of publications (2) tend to systematically dissociate the origins of dependent scattering from multiple scattering phenomena even in white paint films.
Keeping the above commentary in mind, the first objective of this study is to clarify the relationship between these two scattering regimes and to show that the process of dependent scattering of light in white paint films containing TiO2 pigments is only one particular manifestation of the multiple scattering phenomena described within the Foldy-Lax formalism.
The EM scattering from this composite model in Fig.
Refer to Johnson's four-path scattering model [13], the EM coupling interactions between the targets and the sea surface are computed in an iterative way.
The interaction fields [E.sup.s.sub.st] and [E.sup.s.sub.ts] are the scattering fields from target to rough surface and from rough surface to target, respectively.
In order to make it more efficient, a rule for 2-D truncated rough surface area in bi-static scattering problem is proposed under the plane wave illumination based on the scattering mechanism of the rough surface.
The scattering model of a 3-D object above a 2-D random dielectric rough surface is approached in this section.