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تسجيل مستخدم جديدالتقارب الديبول المنفصل لمحاكاة تحليل الضوء بواسطة جسيمات كبيرة أكثر من طول الموجة
The discrete dipole approximation for simulation of light scattering by particles much larger than the wavelength
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وفي هذا المخطوط نحاول دراسة قدرات التقاط المفرد التقريبي (DDA) لمحاكاة الانعكاس من الجسيمات الأكبر من طول الموجة المدخلة، ونصف نصا متاحا على الإنترنت من البرنامج الحاسوبي المحسن DDA الذي يعالج العدد الكبير من المفردات المطلوبة لهذه المحاكاة. وتم عرض المحاكاة الرقمية للانعكاس الضوئي على الكرات بحجم المعلمات x تصل إلى 160 و 40 لمؤشر الشكل الضوئي m = 1.05 و 2 على التوالي ومقارنتها مع النتائج الدقيقة لنظرية مي. وتزيد الأخطاء في كلا الكميات المنعكسة الإجمالية والموجبة عند تزايد m ولا يوجد تبعية نظامية على x. وتزيد الوقت الحسابي بشكل سريع مع كل من x و m، وتصل القيم إلى أكثر من أسبوعين على مجموعة من 64 معالج. والميزة الرئيسية للبرنامج الحاسوبي هي القدرة على توزيع محاكاة DDA واحدة على مجموعة من الحاسوبات، مما يسمح له بمحاكاة الانعكاس الضوئي على الجسيمات الكبيرة جدا، مثل الأشياء التي يتم اعتبارها في هذا المخطوط. وتم مناقشة القيود الحالية وطرق التحسين المحتملة.
In this manuscript we investigate the capabilities of the Discrete Dipole Approximation (DDA) to simulate scattering from particles that are much larger than the wavelength of the incident light, and describe an optimized publicly available DDA computer program that processes the large number of dipoles required for such simulations. Numerical simulations of light scattering by spheres with size parameters x up to 160 and 40 for refractive index m=1.05 and 2 respectively are presented and compared with exact results of the Mie theory. Errors of both integral and angle-resolved scattering quantities generally increase with m and show no systematic dependence on x. Computational times increase steeply with both x and m, reaching values of more than 2 weeks on a cluster of 64 processors. The main distinctive feature of the computer program is the ability to parallelize a single DDA simulation over a cluster of computers, which allows it to simulate light scattering by very large particles, like the ones that are considered in this manuscript. Current limitations and possible ways for improvement are discussed.
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We performed a rigorous theoretical convergence analysis of the discrete dipole approximation (DDA). We prove that errors in any measured quantity are bounded by a sum of a linear and quadratic term in the size of a dipole d, when the latter is in th
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