Thesis (Ph. D.)--University of Oregon, 2007. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 231-242). Also available for download via the World Wide Web; free to University of Oregon users.

Thesis (M.S. in Civil and Environmental Engineering)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1997. / Includes bibliographical references: p. 96-99.

Thesis (Ph. D.)--University of Wisconsin, 1966. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1967. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Finite amplitude planetary waves are studied on a homogeneous fluid on both the rotating sphere and on a mid-latitude β-plane. The integrated equations of motion are rederived both on the rotating sphere, in a spherical polar co-ordinate system whose axis is tilted relative to the rotation axis, and on a mid-latitude β-plane. The linear solutions are re-examined and the errors associated with the non-divergent and the β-plane approximations are each shown to be about 10 to 15% for waves of a few thousand kilometers wavelength. Using the integrated equations of motion both on the sphere and on the β-plane, the linear non-divergent Rossby wave solutions are shown to be exact finite amplitude solutions. An exact topographic wave solution is also given for the case of an exponential depth profile. Such behaviour is not found for the divergent waves. Using a Stokes-type expansion in terms of an amplitude parameter, the second order solution for divergent Rossby waves is obtained, and it is found that, as in surface gravity wave theory, the first order correction to the phase velocity is zero. It is also shown that the linear non-divergent Rossby wave solution on a uniformly sheared zonal current is not a finite amplitude solution, and the second order solution is then calculated. Once again, the phase speed is correct to the first order. A class of long waves of permanent form analogous to the solitary and cnoidal waves of surface wave theory is obtained for a β-plane channel of either constant or exponentially varying depth. Such waves are found to exist in the divergent case in the absence of any zonal current; however, if the divergence is weak, or if the non-divergent approximation is made , then it is found, as it was by Larsen (1965), that these waves will exist only in the presence of a weakly sheared zonal current. On the exponential depth profile, such waves exist in the absence of a sheared zonal current, even if the non-divergent approximation is made. It is suggested that such waves may also exist trapped along long ocean ridges or scarps. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

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published_or_final_version / Physics / Master / Master of Philosophy

We study the propagation of waves in spatially non-homogeneous media focusing on Schrodinger’s equation of quantum mechanics and Maxwell’s equations of electromagnetism. We assume that medium variation occurs over two distinct length scales: a short ‘fast’ scale with respect to which the variation is periodic, and a long ‘slow’ scale over which the variation is smooth. Let epsilon denote the ratio of these scales. We focus primarily on the time evolution of asymptotic solutions (as epsilon tends to zero) known as semiclassical wavepackets. Such solutions generalize exact time-dependent Gaussian solutions and ideas of Heller and Hagedorn to periodic media. Our results are as follows: 1) To leading order in epsilon and up to the ‘Ehrenfest’ time-scale t ~ log 1/epsilon, the center of mass and average (quasi-)momentum of the semiclassical wavepacket satisfy the equations of motion of the classical Hamiltonian given by the wavepacket’s Bloch band energy. Our first result is to derive all corrections to these dynamics proportional to epsilon. These corrections consist of terms proportional to the Bloch band’s Berry curvature and terms which describe coupling to the evolution of the wavepacket envelope. These results rely on the assumption that the wavepacket’s Bloch band energy is non-degenerate. 2) We then consider the case where, in one spatial dimension, a semiclassical wavepacket is incident on a Bloch band crossing, a point in phase space where the wavepacket’s Bloch band energy is degenerate. By a rigorous matched asymptotic analysis, we show that at the time the wavepacket meets the crossing point a second wavepacket, associated with the other Bloch band involved in the crossing, is excited. Our result can be seen as a rigorous justification of the Landau-Zener formula in this setting. 3) Our final result generalizes the recent work of Fefferman, Lee-Thorp, and Weinstein on one-dimensional ‘edge’ states. We characterize the bound states of a Schrodinger operator with a periodic potential perturbed by multiple well-separated domain wall ‘edge’ modulations, by proving a theorem on the near zero eigenstates of an emergent Dirac operator.