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The solution of the wave equation in the envelope approximation with temporal corrections for a laser pulse propagating in a medium where the Kerr effect, field ionization, and associated absorption take place, is obtained through a…

Optics · Physics 2020-02-19 F. Vidal

The paper is concerned with overlapping domain decomposition and exponential time differencing for the diffusion equation discretized in space by cell-centered finite differences. Two localized exponential time differencing methods are…

Numerical Analysis · Mathematics 2017-11-08 Thi-Thao-Phuong Hoang , Lili Ju , Zhu Wang

Nonlinear and nonlocal effects are discussed in the interaction of laser fields with thermal Rydberg atoms in electromagnetically induced transparency configuration. We show that under the crucial approximation that the time variation in…

Atomic Physics · Physics 2016-09-21 Lida Zhang , Jörg Evers

Analytic solutions to the nonlinear radiation diffusion equation with an instantaneous point source for a non-homogeneous medium with a power law spatial density profile, are presented. The solutions are a generalization of the well known…

Fluid Dynamics · Physics 2021-06-02 Menahem Krief

The problem of the emergence of wave dispersion due to the heterogeneity of a transmission line (TL) is considered. An exactly solvable model helps to better understand the physical process of a signal passing through a non-uniform section…

Applied Physics · Physics 2024-02-20 A. B. Shvartsburg , S. N. Artekha , N. S. Artekha

We present an algorithm for solving the linear dispersion relation in an inhomogeneous, magnetised, relativistic plasma. The method is a generalisation of a previously reported algorithm that was limited to the homogeneous case. The…

Astrophysics · Physics 2009-11-13 J. Pétri , J. G. Kirk

Diffusion models have recently emerged as powerful generative priors for solving inverse problems. However, training diffusion models in the pixel space are both data-intensive and computationally demanding, which restricts their…

Computer Vision and Pattern Recognition · Computer Science 2024-04-17 Bowen Song , Soo Min Kwon , Zecheng Zhang , Xinyu Hu , Qing Qu , Liyue Shen

We study the problem of a temporal discontinuity in the permittivity of an unbounded medium with Lorentzian dispersion. More specifically, we tackle the situation in which a monochromatic plane wave forward-travelling in a (generally lossy)…

Optics · Physics 2025-09-24 Diego M. Solís , Raphael Kastner , Nader Engheta

Pseudo-Hermitian operators appear in the solution of Maxwell's equations for stationary non-dispersive media with arbitrary (space-dependent) permittivity and permeability tensors. We offer an extension of the results in this direction to…

Quantum Physics · Physics 2015-05-18 Ali Mostafazadeh

Temporally modulated optical media are important in both abstract and applied applications, such as spacetime transformation optics, relativistic laser-plasma interactions, and dynamic metamaterials. Here we investigate the behaviour of…

The present paper is concerned with a space-time homogenization problem for nonlinear diffusion equations with periodically oscillating (in space and time) coefficients. Main results consist of a homogenization theorem (i.e., convergence of…

Analysis of PDEs · Mathematics 2020-07-21 Goro Akagi , Tomoyuki Oka

The problem of radio wave reflection from an optically thick plane monotonous layer of magnetized plasma is considered at present work. The plasma electron density irregularities are described by spatial spectrum of an arbitrary form. The…

Plasma Physics · Physics 2009-10-31 N. A. Zabotin , A. G. Bronin , G. A. Zhbankov

We show that radiation from complex and inherently random but correlated wave sources can be modelled efficiently by using an approach based on the Wigner distribution function. Our method exploits the connection between correlation…

Chaotic Dynamics · Physics 2015-09-30 Gabriele Gradoni , Stephen Creagh , Gregor Tanner , Christopher Smartt , David Thomas

One of the main challenges in diffusion-based molecular communication is dealing with the non-linearity of reaction-diffusion chemical equations. While numerical methods can be used to solve these equations, a change in the input signals or…

Information Theory · Computer Science 2021-06-04 Hamidreza Abin , Amin Gohari , Masoumeh Nasiri-Kenari

We present a novel computational methodology for solving the scalar nonlinear Helmholtz equation (NLH) that governs the propagation of laser light in Kerr dielectrics. The methodology addresses two well-known challenges in nonlinear optics:…

Mathematical Physics · Physics 2009-12-07 Guy Baruch , Gadi Fibich , Semyon V. Tsynkov

We formulate the problem of a two-level system in a linearly polarized laser field in terms of a nonlinear Riccati-type differential equation and solve the equation analytically in time intervals much shorter than half the optical period.…

Quantum Physics · Physics 2007-05-23 R. Parzynski , M. Sobczak , A. Plucinska

We study the coherence in time and space of electromagnetic fields propagated through complex media. Whether for localization, imaging or telecommunication, the development of dedicated numerical techniques is generally based on the…

Computational Physics · Physics 2022-04-21 Thomas Fromenteze , Matthieu Davy , Okan Yurduseven , Yann Marie-Joseph , Cyril Decroze

The nonlinear interaction between intense laser light and a quantum plasma is modeled by a collective Dirac equation coupled with the Maxwell equations. The model is used to study the nonlinear propagation of relativistically intense laser…

Plasma Physics · Physics 2015-05-28 Bengt Eliasson , Padma K. Shukla

The geometric representation at a fixed frequency of the wavevector (or dispersion) surface $\omega(\vec k)$ for lossless, homogeneous dielectric--magnetic uniaxial materials is explored, when the elements of the relative permittivity and…

We consider the propagation of acoustic time-harmonic waves in a homogeneous media containing periodic lattices of spherical or cylindrical inclusions. It is assumed that the wavelength has the order of the periods of the lattice while the…

Analysis of PDEs · Mathematics 2019-07-04 Yuri A. Godin , Boris Vainberg