Prof. Juan M. Rius
Professor at Department of Signal Theory and Communications, Universitat Politècnica de Catalunya, Spain
Title of talk: Graphical Electromagnetic Computing (GRECO) for high-frequency RCS prediction
Biograhy: Juan M. Rius was Born in Barcelona, Spain, in 1963. He received the "Ingeniero de Telecomunicación'' degree in 1987 and the "Doctor Ingeniero'' degree in 1991, both from the Universitat Politècnica de Catalunya (UPC), Barcelona, Spain. In 1985 he joined the Electromagnetic and Photonic Engineering group (now ComSensLab) at UPC, Department of Signal Theory and Communications (TSC), where he currently holds a position of "Catedrático'' (equivalent to Full Professor).
From 1985 to 1988 he developed a new inverse scattering algorithm for microwave tomography in cylindrical geometry systems. Since 1989 he has been engaged in the research for new and efficient methods for numerical computation of electromagnetic scattering and radiation. He is the developer of the Graphical Electromagnetic Computation (GRECO) approach for high-frequency RCS computation, the Integral Equation formulation of the Measured Equation of Invariance (IE-MEI) and the Multilevel Matrix Decomposition Algorithm (MLMDA) in 3D. Current interests are the numerical simulation of electrically large antennas and scatterers.
He has held positions of "Visiting Professor'' at EPFL (Lausanne) from May 1, 1996 to October 31, 1996; "Visiting Fellow'' at City University of Hong Kong from January 3, 1997 to February 4, 1997; "CLUSTER chair'' at EPFL from December 1, 1997 to January 31, 1998; and "Visiting Professor'' at EPFL from April 1, 2001 to June 30, 2001.
He has more than 70 papers published or accepted in refereed international journals (WoS) and more than 200 in international conference proceedings.
Prof. Herbert De Gersem
Institute for Accelerator Science and Electromagnetic Fields (TEMF), TU Darmstadt, Germany
Title of talk: Modelling and Simulation of Magnetoquasistatic and Electroquasistatic Fields
Abstract: Magnetoquasistatic field problems arise in, e.g., transformers, electric machines and superconducting magnets. Electroquasistatic field problems arise in high-voltage engineering and on printed circuit boards. Both are expressed by a nonlinear parabolic partial differential equation, which is typically discretised by finite elements on an unstructured tetrahedral mesh and time-stepped by implicit methods. The talk addresses contemporary challenges such as, e.g., the increasing level of detail, multiphysical phenomena, multirate behaviour and nontrivial materials. Recent developments in numerical methods dedicated to the quasistatic setting will be discussed, e.g., hybrid spatial discretisation schemes, field-circuit coupling, multirate time stepping and sparse surrogate modelling. The methods will be illustrated by examples from electrical engineering and accelerator science.
Biography: Herbert De Gersem is born in 1971 and obtained the MSc and PhD degrees in electrical engineering at the KU Leuven (Belgium) in 1994 and 2001, respectively. From 2001 to 2006, he worked as a postdoc at TU Darmstadt (Germany). Since 2006, he is an associated professor at the KU Leuven. Since 2014, he is a full professor at the TU Darmstadt (www.temf.de). He authored and co-authored more than 130 publications in international journals. His major research topics are electromagnetic field simulation with volumetric discretisation methods (finite element method, finite integration technique, discontinuous Galerkin method) and the application thereof to electrical energy transducers (machines, actuators, transformers) and accelerator components (conventional and superconductive magnets and resonating cavities).
Dr. Patrick Joly
Unité de Mathématiques Appliquées, École Nationale Supérieure de Techniques Avancées, Paris, France
Title of talk: Time domain models for dispersive electromagnetic media and Perfectly Matched Layers
Abstract: This talk, with two parts, reports about results obtained in collaboration with E. Bécache, M. Cassier, M. Kachanovska and V. Vinoles.
In the first part, we review and describe the main properties of the mathematical models used for describing the propagation of electromagnetic waves in dispersive media, and more especially the so-called passive media . One essential feature is that the permittivity and permeability of such media are frequency dependent: as a consequence, plane waves in such a media are dispersive and can be back propagating (one speaks then of a negative index material).
We shall that causality and passivity requirements naturally lead to constitutive laws involving so-called Herglotz functions. A particular emphasis will be put on the case of so called local media when the permeability and the permittivity of the medium are rational functions of the frequency: this leads to Lorentz models. In this case we shall describe in detail the propagation of plane waves, their dispersion relation and related notions of frequency bands, forward and back propagating modes.
In the second part, I will show that the well known approach of Perfectly Matched Layers for bounding a computational domain fails to be stable (if the classical Bérenger approach is applied) in negative index materials and we shall show how to construct new stable PML's in this context .
 Maxence Cassier, Patrick Joly, Maryna Kachanovzka, Mathematical models for dispersive electromagnetic waves: An overview (2017) Computers and Mathematics with Applications, vol. 74 (11), pp. 2792-2830
 Éliane Bécache, Patrick Joly, Valentin Vinoles, On the analysis of perfectly matched layers for a class of dispersive media and application to negative index metamaterials (2018) Mathematics of Computations, vol. 87, pp. 2775-2810
Biography: Patrick Joly was born in Paris in 1957. He got an engineering degree from Ecole Centrale de Paris in 1980, a PhD in Mathematics from Paris Dauphine University and in 1987 the « These d’État » (equivalent of the Habilitation) in mathematics from the same University. In september 1980, he got a Junior Researcher position
at INRIA, a French Research Institute in Applied Mathematics and Computer Science where he has done all his carrer since then (apart from two years as a Mathematics professor at Dauphine). He is presently Director of Research of Exceptional Class (since 2007). He has in parallel occupied several part time teaching positions in various universities and engineering schools of Paris and its area, in particular at Ecole Polytechnique and Ensta.
His research is dedicated to mathematics applied to wave propagation phenomena in various ways : this includes the design and analysis of mathematical models as well as the design and analysis of related numerical methods in various fdomains of application including acoustics ans electromagnetism. His range of expertise goes from pure theory to scientific computing. He was the leader of the Team Poems, dedicated to mathematics for waves, from 1992 to 2014. He is also one of the creators of the series of the Waves Conferences.