Plane wave scattering by a spherical di-electric particle in motion : a relativistic extension of the Mie theory

Light scattering from small spherical particles has applications in a vast number of disciplines including astrophysics, meteorology optics and particle sizing. Mie theory provides an exact analytical characterization of plane wave scattering from spherical dielectric objects. There exist many variants of the Mie theory where fundamental assumptions of the theory has been relaxed to make generalizations. Notable such extensions are generalized Mie theory where plane waves are replaced by optical beams, scattering from lossy particles, scattering from layered particles or shells and scattering of partially coherent (non-classical) light. However, no work has yet been reported in the literature on modifications required to account for scattering when the particle or the source is in motion relative to each other. This is an important problem where many applications can be found in disciplines involving moving particle size characterization. In this paper we propose a novel approach, using special relativity, to address this problem by extending the standard Mie theory for scattering by a particle in motion with a constant speed, which may be very low, moderate or comparable to the speed of light. The proposed technique involves transforming the scattering problem to a reference frame co-moving with the particle, then applying the Mie theory in that frame and transforming the scattered field back to the reference frame of the observer.

Il sistema di partito predominante : problemi e prospettive

È difficile sopravvalutare l’importanza di Parties and Party Systems. Si tratta di uno studio, che, caso raro nelle scienze politiche esociali, è diventato un classico per gli studiosi di partiti e sistemi di partito.Ha rappresentato il più importante quadro teorico per l’analisi e lacategorizzazione dei sistemi di partito, ha introdotto nuovo categories disistemi di partito rinnovando e raffinando la tipologia formulata inizialmenteda Duverger, e ha spiegato come la stabilità e l’efficacia dei governi,così come la stabilità dei sistemi politici, sia influenzata dai patterndi interazione inter-partitica. Per i suoi molti e significativi contributi,Parties and Party Systems ha rappresentato il punto di riferimento e lapietra di paragone per tutti gli studi successivi.