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dc.contributor.authorHesse, Evelyn
dc.contributor.authorTaylor, Laurence
dc.contributor.authorCollier, Christopher T.
dc.contributor.authorPenttila, Antti
dc.contributor.authorNousiainen, Timo
dc.contributor.authorUlanowski, Zbigniew
dc.date.accessioned2018-09-04T00:12:55Z
dc.date.available2018-09-04T00:12:55Z
dc.date.issued2018-10-01
dc.identifier.citationHesse , E , Taylor , L , Collier , C T , Penttila , A , Nousiainen , T & Ulanowski , Z 2018 , ' Discussion of a physical optics method and its application to absorbing smooth and slightly rough hexagonal prisms ' , Journal of Quantitative Spectroscopy and Radiative Transfer , vol. 218 , pp. 54-67 . https://doi.org/10.1016/j.jqsrt.2018.06.019
dc.identifier.issn0022-4073
dc.identifier.otherPURE: 14996235
dc.identifier.otherPURE UUID: ea4a7034-c73a-48eb-86bf-e602d634353d
dc.identifier.otherScopus: 85050144056
dc.identifier.otherORCID: /0000-0003-4761-6980/work/62748721
dc.identifier.otherORCID: /0000-0002-2721-7600/work/62749833
dc.identifier.urihttp://hdl.handle.net/2299/20501
dc.description.abstractThree different mathematical solutions of a physical optics model for far field diffraction by an aperture due to Karczewski and Wolf are discussed. Only one of them properly describes diffraction by an aperture and can, by applying Babinet's principle, be used to model diffraction by the corresponding plane obstacle, and by further approximation, diffraction by a particle. Studying absorbing scatterers allows a closer investigation of the external diffraction component because transmission is negligible. The physical optics model has been improved on two aspects: (i) To apply the diffraction model based on two-dimensional apertures more accurately to three-dimensional objects, a size parameter dependent volume obliquity factor is introduced, thus reducing the slightly overestimated side scattering computed for three-dimensional objects. (ii) To compensate simplifications in the underlying physical optics diffraction model for two-dimensional apertures [26] a size parameter dependent cross polarisation factor is implemented. It improves cross polarisation for diffraction and reflection by small particle facets. 2D patterns of P 11, –P 12/P 11 and P 22/P 11 and their azimuthal averages for slightly rough absorbing hexagonal prisms in fixed orientation are obtained and compared with results from the discrete dipole approximation. For particle orientations where shadowing is not negligible, improved phase functions are obtained by using a new method where the incident beam is divided into sub-beams with small triangular cross sections. The intersection points of the three sub-beam edges with the prism define the vertices of a triangle, which is treated by the beam tracer as an incidence-facing facet. This ensures that incident facing but shadowed crystal facets or regions thereof do not contribute to the phase functions. The method captures much of the fine detail contained in 2D scattering patterns obtained with DDA. This is important as speckle can be used for characterizing the size and roughness of small particles such as ice crystals.en
dc.format.extent14
dc.language.isoeng
dc.relation.ispartofJournal of Quantitative Spectroscopy and Radiative Transfer
dc.rightsEmbargoed
dc.subjectAbsorbing facetted particle
dc.subjectDiffraction
dc.subjectLight scattering
dc.subjectRough particle
dc.subjectRadiation
dc.subjectAtomic and Molecular Physics, and Optics
dc.subjectSpectroscopy
dc.titleDiscussion of a physical optics method and its application to absorbing smooth and slightly rough hexagonal prismsen
dc.contributor.institutionCentre for Atmospheric and Climate Physics Research
dc.contributor.institutionLight Scattering & Radiactive Properties
dc.contributor.institutionSchool of Physics, Astronomy and Mathematics
dc.description.statusPeer reviewed
dc.date.embargoedUntil2019-07-17
dc.identifier.urlhttp://www.scopus.com/inward/record.url?scp=85050144056&partnerID=8YFLogxK
dc.relation.schoolSchool of Physics, Astronomy and Mathematics
dc.description.versiontypeFinal Accepted Version
dcterms.dateAccepted2018-10-01
rioxxterms.versionAM
rioxxterms.versionofrecordhttps://doi.org/10.1016/j.jqsrt.2018.06.019
rioxxterms.licenseref.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/
rioxxterms.licenseref.startdate2019-07-17
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue
herts.date.embargo2019-07-17
herts.rights.accesstypeEmbargoed


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