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dc.contributor.advisorNewell, Alan C.en_US
dc.contributor.authorPowell, James Alan.
dc.creatorPowell, James Alan.en_US
dc.date.accessioned2011-10-31T17:26:21Z
dc.date.available2011-10-31T17:26:21Z
dc.date.issued1990en_US
dc.identifier.urihttp://hdl.handle.net/10150/185055
dc.description.abstractArguments are presented for understanding the selection of speed and the nature of the fronts which join stable and unstable states on both the subcritical and the supercritical side of first order phase transitions. Subcritically, a unique front exists for a given set of parameter values, corresponding to a unique connection between metastable states. In the phase space of the Galilean ODE, uniqueness arises from the non-perturbability of a connection between saddle points corresponding to plane waves and ground states. Unique connections are shown to be special solutions which have the Painleve property, and such solutions are found using the WTC method. ODE trajectories corresponding to unique front solutions are shown to satisfy van Saarloos' reduction of order, which suggests that "integrability" for solutions corresponds to the existence of non-generic conservation laws. Supercritically, observable front behavior occurs when the asymptotic spatial structure of a trajectory in the Galilean ODE corresponds to the most unstable temporal mode in the governing PDE. This selection criterion distinguishes between a "nonlinear" front, which originates in the first order nature of the bifurcation, and a "linear" front. The nonlinear front is a continuous deformation of the unique subcritical fronts, is a strongly heteroclinic trajectory in the ODE, and is an integrable solution for the PDE. Many of the characteristics of the linear front are obtained from a steepest descents linear analysis due to Kolmogorov. Its connection with global stability, and in particular with arguments based on a Liapunov functional, is pursued. Liapunov functionals illustrate that stable front behavior arises from the most unstable mode of the PDE, but the stability-based selection criterion is valid even where the Liapunov functional doesn't exist.
dc.language.isoenen_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.subjectEngineeringen_US
dc.subjectPhysicsen_US
dc.titleNonlinear fronts near a first-order phase transition.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.identifier.oclc708252081en_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.contributor.committeememberLevermore, Charles D.en_US
dc.contributor.committeememberGreenlee, W. Martinen_US
dc.contributor.committeememberFasel, Hermannen_US
dc.contributor.committeememberChow, Kwoken_US
dc.identifier.proquest9025075en_US
thesis.degree.disciplineApplied Mathematicsen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.namePh.D.en_US
refterms.dateFOA2018-08-23T00:06:02Z
html.description.abstractArguments are presented for understanding the selection of speed and the nature of the fronts which join stable and unstable states on both the subcritical and the supercritical side of first order phase transitions. Subcritically, a unique front exists for a given set of parameter values, corresponding to a unique connection between metastable states. In the phase space of the Galilean ODE, uniqueness arises from the non-perturbability of a connection between saddle points corresponding to plane waves and ground states. Unique connections are shown to be special solutions which have the Painleve property, and such solutions are found using the WTC method. ODE trajectories corresponding to unique front solutions are shown to satisfy van Saarloos' reduction of order, which suggests that "integrability" for solutions corresponds to the existence of non-generic conservation laws. Supercritically, observable front behavior occurs when the asymptotic spatial structure of a trajectory in the Galilean ODE corresponds to the most unstable temporal mode in the governing PDE. This selection criterion distinguishes between a "nonlinear" front, which originates in the first order nature of the bifurcation, and a "linear" front. The nonlinear front is a continuous deformation of the unique subcritical fronts, is a strongly heteroclinic trajectory in the ODE, and is an integrable solution for the PDE. Many of the characteristics of the linear front are obtained from a steepest descents linear analysis due to Kolmogorov. Its connection with global stability, and in particular with arguments based on a Liapunov functional, is pursued. Liapunov functionals illustrate that stable front behavior arises from the most unstable mode of the PDE, but the stability-based selection criterion is valid even where the Liapunov functional doesn't exist.


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