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Title:Numerical methods for solar tomography in the STEREO era
Author(s):Hewett, Russell J.
Director of Research:Heath, Michael T.
Doctoral Committee Chair(s):Heath, Michael T.
Doctoral Committee Member(s):Kamalabadi, Farzad; Olson, Luke N.; Hart, John C.; St. Cyr, Orville C.
Department / Program:Computer Science
Discipline:Computer Science
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Solar Corona
Constrained Optimization
Kalman Filter
Tomography
Dynamic Tomography
Phase Fields
Level sets
Projection Matrix
Dense Ray Tracing
Abstract:In this thesis, we propose several advances in the numerical and computational algorithms that are used to determine tomographic estimates of physical parameters in the solar corona. We focus on methods for both global dynamic estimation of the coronal electron density and estimation of local transient phenomena, such as coronal mass ejections, from empirical observations acquired by instruments onboard the STEREO spacecraft. We present a first look at tomographic reconstructions of the solar corona from multiple points-of-view, which motivates the developments in this thesis. In particular, we propose a method for linear equality constrained state estimation that leads toward more physical global dynamic solar tomography estimates. We also present a formulation of the local static estimation problem, i.e., the tomographic estimation of local events and structures like coronal mass ejections, that couples the tomographic imaging problem to a phase field based level set method. This formulation will render feasible the 3D tomography of coronal mass ejections from limited observations. Finally, we develop a scalable algorithm for ray tracing dense meshes, which allows efficient computation of many of the tomographic projection matrices needed for the applications in this thesis.
Issue Date:2012-02-01
URI:http://hdl.handle.net/2142/29562
Rights Information:Copyright 2011 Russell J. Hewett
Date Available in IDEALS:2014-02-01
Date Deposited:2011-12


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