UBC Theses and Dissertations
Simulations of radiation pressure experiments Bethune-Waddell, Maximilien
Electromagnetic radiation, such as light, can exert a force on objects. This phenomena is referred to as radiation pressure. A popular example would be the radiation pressure from the sun which is presently the only force pushing NASA's Kepler II satellite out of our solar system. The most important material property relevant to radiation pressure is the refractive index n. The vacuum of space around the Kepler satellite has a refractive index of n=1. For this situation our ability to model radiation pressure is quite certain. There has been a debate over the last century on how to model radiation pressure in the presence of matter, where the refractive index of the surrounding medium can be n >1. Five prevalent models exist for electrodynamics, namely the Abraham, Minkowksi, Einstein-Laub, Chu, or the Amperian formulations. Various electrodynamic theories presented over the last century have differences that only arise in exotic situations such as objects in liquid environments, material moving at relativistic speeds, and short timescales difficult to measure. Because technology has now advanced to potentially include these situations, this thesis addresses the renewed attention this debate requires. Each of these models are tested against two criteria using a simulation tool that solves for both electromagnetic and fluid dynamic phenomena. First, their compliance with the conservation laws of energy, momentum, and center-of-mass velocity. Second, their accord with experimental results. A simulation environment is used to calculate the conserved quantities and observable effects that each model predicts under various experimental conditions. The simulation tool is a Matlab script that allows us to consider and compare the results of many experiments simultaneously. Five significant experiments are analyzed in this thesis: the radiation pressure observed on metallic and dielectric mirrors, the deformation of a water-air interface, the deformation of a fluid-fluid interface, the displacement of polystyrene beads submerged in water, and the displacement of an oil droplet on a water surface. This thesis reaches the conclusion that not enough data is available from past experiments to verify a single electrodynamic theory. Our work suggests simple new experiments that could.
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