The Experts below are selected from a list of 600 Experts worldwide ranked by ideXlab platform
Nikolay I. Zheludev - One of the best experts on this subject based on the ideXlab platform.
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pulse generation scheme for flying electromagnetic doughnuts
Physical Review B, 2018Co-Authors: Nikitas Papasimakis, V A Fedotov, T.a. Raybould, Ian J. Youngs, Din Ping Tsai, Nikolay I. ZheludevAbstract:Transverse electromagnetic plane waves are fundamental solutions of Maxwells Equations. It is less known that a radically different type of solutions has been described theoretically, but has never been realized experimentally, that exist only in the form of short burst of electromagnetic energy propagating in free-space at the speed of light. They are distinguished from transverse waves by a doughnut-like configuration of electric and magnetic fields with a strong field component along the propagation direction. Here, we demonstrate numerically that such Flying Doughnuts can be generated from conventional pulses using a singular metamaterial converter designed to manipulate both the spatial and spectral structure of the input pulse. The ability to generate Flying Doughnuts is of fundamental interest, as they shall interact with matter in unique ways, including non-trivial field transformations upon reflection from interfaces and the excitation of toroidal response and anapole modes in matter, thus offering new opportunities for telecommunications, sensing, and spectroscopy.
Olov Agren - One of the best experts on this subject based on the ideXlab platform.
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curl free positive definite form of time harmonic Maxwells Equations well suitable for iterative numerical solving
arXiv: Computational Physics, 2020Co-Authors: V E Moiseenko, Olov AgrenAbstract:A new form of time-harmonic Maxwells Equations is developed and proposed for numerical modeling. It is written for the magnetic field strength, electric displacement, vector potential and the scalar potential. There are several attractive features of this form. The first one is that the differential operator acting on these quantities is positive. The second is absence of curl operators among the leading order differential operators. The Laplacian stands for the leading order operator in the Equations for the magnetic field strength, vector potential and the scalar potential, while the gradient of divergence stands for the electric displacement. The third feature is absence of space varied coefficients in the leading order differential operators that provides diagonal domination of the resulting matrix of the discretized Equations. A simple example is given to demonstrate the applicability of this new form of time-harmonic Maxwells Equations.
V E Moiseenko - One of the best experts on this subject based on the ideXlab platform.
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curl free positive definite form of time harmonic Maxwells Equations well suitable for iterative numerical solving
arXiv: Computational Physics, 2020Co-Authors: V E Moiseenko, Olov AgrenAbstract:A new form of time-harmonic Maxwells Equations is developed and proposed for numerical modeling. It is written for the magnetic field strength, electric displacement, vector potential and the scalar potential. There are several attractive features of this form. The first one is that the differential operator acting on these quantities is positive. The second is absence of curl operators among the leading order differential operators. The Laplacian stands for the leading order operator in the Equations for the magnetic field strength, vector potential and the scalar potential, while the gradient of divergence stands for the electric displacement. The third feature is absence of space varied coefficients in the leading order differential operators that provides diagonal domination of the resulting matrix of the discretized Equations. A simple example is given to demonstrate the applicability of this new form of time-harmonic Maxwells Equations.
Jan S. Hesthaven - One of the best experts on this subject based on the ideXlab platform.
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nodal discontinuous galerkin methods algorithms analysis and applications
2007Co-Authors: Jan S. Hesthaven, T WarburtonAbstract:The text offers an introduction to the key ideas, basic analysis, and efficient implementation of discontinuous Galerkin finite element methods (DG-FEM) for the solution of partial differential Equations. All key theoretical results are either derived or discussed, including an overview of relevant results from approximation theory, convergence theory for numerical PDEs, orthogonal polynomials etc. Through embedded Matlab codes, the algorithms are discussed and implemented for a number of classic systems of PDEs, e.g., Maxwells Equations, Euler Equations, incompressible Navier-Stokes Equations, and Poisson- and Helmholtz Equations. These developments are done in detail inone and two dimensions on general unstructured grids with high-order elements and all essential routines for 3D extensions are also included and discussed briefly. The three appendices contain an overview of orthogonal polynomials and associated library routines used throughout, a brief introduction to grid generation, and an overview of the associated software (where to get it, list of variables etc). A variety of exercises are included at the end of most chapters.
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Modeling of the frozen mode phenomenon and its sensitivity using discontinuous Galerkin methods
Communications in Computational Physics, 2007Co-Authors: S. Chun, Jan S. HesthavenAbstract:We investigate the behavior and sensitivity of the frozen mode phenomenon in finite structures with anisotropic materials, including both magnetic materials and non-normal incidence. The studies are done by using a high-order accurate discontinu- ous Galerkin method for solving Maxwells Equations in the time domain. We confirm the existence of the phenomenon also in the time-domain and study carefully the impact of the finite crystal on the frozen mode. This sets the stage for a thorough study of the robustness of the frozen mode phenomenon, resulting in guidelines for which design parameters are most sensitive and acceptable tolerances.
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fdtd method for Maxwells Equations in complex geometries
Annual Review of Progress in Applied Computational Electromagnetics, 2000Co-Authors: Adi Ditkowski, K Dridi, Jan S. HesthavenAbstract:A stable second order Cartesian grid finite difference scheme for the solution of Maxwells Equations is presented. The scheme employs a staggered grid in space and represents the physical location of the material and metallic boundaries correctly, hence eliminating problems caused by staircasing, and, contrary to the popular Yee scheme, enforces the correct jump-conditions on the field components across material interfaces. To validate the analysis several test cases are presented, showing an improvement of typically 1-2 orders of accuracy at little or none additional computational cost over the Yee scheme, which in most cases exhibits first order accuracy.
Nikitas Papasimakis - One of the best experts on this subject based on the ideXlab platform.
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pulse generation scheme for flying electromagnetic doughnuts
Physical Review B, 2018Co-Authors: Nikitas Papasimakis, V A Fedotov, T.a. Raybould, Ian J. Youngs, Din Ping Tsai, Nikolay I. ZheludevAbstract:Transverse electromagnetic plane waves are fundamental solutions of Maxwells Equations. It is less known that a radically different type of solutions has been described theoretically, but has never been realized experimentally, that exist only in the form of short burst of electromagnetic energy propagating in free-space at the speed of light. They are distinguished from transverse waves by a doughnut-like configuration of electric and magnetic fields with a strong field component along the propagation direction. Here, we demonstrate numerically that such Flying Doughnuts can be generated from conventional pulses using a singular metamaterial converter designed to manipulate both the spatial and spectral structure of the input pulse. The ability to generate Flying Doughnuts is of fundamental interest, as they shall interact with matter in unique ways, including non-trivial field transformations upon reflection from interfaces and the excitation of toroidal response and anapole modes in matter, thus offering new opportunities for telecommunications, sensing, and spectroscopy.