Coupling of continuum mechanics and electrodynamics [article]

Felix Alexander Reich, Technische Universität Berlin, Technische Universität Berlin, Wolfgang H. Müller
2017
In the literature, many models of electromagnetic momentum are proposed. Each model implies a form of the electromagnetic force density, which acts as a source in the mechanical momentum balance. The debate as to which model of the electromagnetic force is "correct" for arbitrary materials and processes is ongoing. Most authors argue in favor or against specific models by virtue of thought experiments, e.g, with light waves. The topic of this work is to show that experiments conducted on a
more » ... scale can conclusively eliminate models from the pool of generally applicable force models. Any electromagnetic force model predicts a total force that acts on a body as well as a local force distribution. Both predictions can be used experimentally. To do so, experiments are conceived and conducted on a macro scale in this thesis in order to test the theoretical mechanical predictions of some selected electromagnetic force models. By comparing theoretical results with experimental findings, certain candidates for a generally applicable electromagnetic force model can be excluded. The first experiment considers the total electromagnetic forces in a magnetostatic setting. Here, the total axial force between two equal coaxially aligned permanent cylindrical magnets is investigated. To start, the magnetic field produced by cylindrical permanent magnets is computed analytically. Using this result, the axial force between the cylinders is also obtained analytically. All considered electromagnetic force models yield an equal force prediction that agrees with conducted experiments. An analysis shows that (most) electromagnetic force models yield equal predictions for the total force in static settings. Also, the experimental results show that if a model satisfies some requirements w.r.t. the Lorentz force, its prediction of the total force is exact in a magnetostatic setting. To show the implications of local effects, two similar problems are considered: an elastic and homogeneously magnetized sphere, and an elastic and linear [...]
doi:10.14279/depositonce-6518 fatcat:jxzukgslj5fhpol5jssjzqqsqm