Magnetoacoustic wave propagation in planetary magnetospheres

In recent times space researchers have focused on slow magnetoacoustic wave detection in magnetospheres. The increased attention is partly due to the slow wave's ability to act as an energy transfer mechanism for magnetosphere phenomena and for solar wind acceleration. Currently, there is disagreement in the space physics community as to whether or not the slow wave has been detected. When attempting to identify magnetoacoustic waves from spacecraft data, researchers have used plane wave theory to model the waves. Plane wave theory is limited in the following ways. First, the approximation is restricted to parallel magnetic fields (planetary magnetic fields are approximately three-dimensional dipoles). Second, plane wave analysis yields limited information on the wave perturbation values (changes in density, velocity, and magnetic fields). Third, plane wave analysis cannot calculate how a three-dimensional wave will evolve or what the evolving wave's perturbation values will be.;The dissertation addresses the limitations listed above using methods developed by mathematical and plasma researchers of the 1940's, 1950's and early 1960's, and then applies the methodology to "magnetosphere like" conditions to simulate evolving magnetoacoustic waves. Specifically, calculations will be shown depicting the evolution of magnetoacoustic waves in arbitrary fields (exemplified by radial and dipole magnetic fields) and for arbitrary initial wave shapes (exemplified by spherical and cylindrical shapes). Perturbation calculation examples for the evolving waves are also included.;A three dimensional magnetoacoustic wave propagation simulation capability is required to understand the nonintuitive cusp shape that an evolving slow wave forms. In space, a satellite would record the cusp shaped slow wave as several wave fronts. This multiple recorded signal concept may be one of the complicating reasons that makes slow wave detection difficult. This dissertation provides simulation examples of what a spacecraft would record for a given initial magnetoacoustic wave shape and strength and known magnetic field and plasma density. The purpose of the simulation capability would be to aid space researchers if they were to design a magnetoacoustic wave experiment to detect slow waves in magnetospheres.;Due to the multitude and scope of the problems confronting researchers and the variety of backgrounds that the researchers possess (physics, electrical engineering, geophysical, mathematical, and aerospace engineering), an attempt was made to review relevant topics to provide part of a foundation for future magnetoacoustic wave research. This review includes a discussion of magnetoacoustic wave properties, a full development of the MHD equations (in SI), and tables of current values (dipole strengths, bow shock locations, etc. ...) for planetary magnetospheres.