Near Fields, Rays, and Multipoles in Wave Scattering Theory

Explore a detailed mathematical seminar presentation that delves into the fascinating world of acoustic wave behavior, focusing on subsonic waves and their role in near fields. Learn about three-dimensional field structures crucial to multiple wave scattering problems, with particular emphasis on the near-field ray structure of high-order rotating multipoles. Discover how these waves, traveling slower than the speed of sound, create 'inhomogeneous' patterns with varying amplitudes in the transverse direction. Examine the geometric visualization of a near field as a 'spinning orange' with alternating high and low pressure regions, and understand its transition to propagating spiral waves in the far field. Follow the collaborative research progress between Professor John Chapman and Stuart Hawkins, exploring new canonical problems and their analytical descriptions through geometric ray theory approaches.