Development and application of 2D and 3D transient electromagnetic inverse solutions based on adjoint Green functions [Elektronische Ressource] : a feasibility study for the spatial reconstruction of conductivity distributions by means of sensitivities / vorgelegt von Roland Martin

Development and application of 2D and 3Dtransient electromagnetic inverse solutionsbased on adjoint Green functions:A feasibility study for the spatial reconstructionof conductivity distributions by means of sensitivitiesI n a u g u r a l – D i s s e r t a t i o nzurErlangung des Doktorgrades(Dr. rer. nat.)der Mathematisch–Naturwissenschaftlichen Fakultätder Universität zu Kölnvorgelegt vonRoland Martinaus HückeswagenKöln 2009Gutachter: Prof. Dr. B. TezkanProf. Dr. A. KemnaTag der mündlichen Prüfung: 22. April 2009AbstractTo enhance interpretation capabilities of transient electromagnetic (TEM) methods, a multi-dimensional inverse solution is introduced, which allows for a explicit sensitivity calculationwith reduced computational effort. The main conservation of computational load is obtainedby solving Maxwell’s equations directly in time domain. This is achieved by means of a highefficient Krylov-subspace technique that is particularly developed for the fast computation ofEM fields in the diffusive regime. Traditional modeling procedures for Maxwell’s equationsyields solutions independently for every frequency or, in the time domain, at a given timethrough explicit time stepping. Because of this, frequency domain methods are renderedextremely time consuming for multi-frequency simulations.