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Knowing the characteristic relaxation time of free electrons in a dense plasma is crucial to our understanding of plasma equilibration and transport. However, experimental investigations of electron relaxation dynamics have been hindered by…

Plasma Physics · Physics 2024-08-27 Yuanfeng Shi , Shenyuan Ren , Hyun-kyung Chung , Justin S. Wark , Sam M. Vinko

Using 1D and 2D PIC simulations, we describe and model the backward ejection of electron bunches when a laser pulse reflects off an overdense plasma with a sharp density gradient on its front side. The dependence on the laser intensity and…

Plasma Physics · Physics 2018-02-01 Maxence Thévenet , Henri Vincenti , Jérôme Faure

Relativistic strongly magnetized plasmas are produced in laboratories thanks to state-of-the-art laser technology but can naturally be found around compact objects such as neutron stars and black holes. Detailed studies of the behaviour of…

Plasma Physics · Physics 2017-05-24 J. Pétri

We develop a general-purpose formulation, based on two-dimensional spectral integrals, for computing electromagnetic fields produced by arbitrarily-oriented dipoles in planar-stratified environments, where each layer may exhibit arbitrary…

Computational Physics · Physics 2014-11-27 K. Sainath , F. L. Teixeira , B. Donderici

Single-particle imaging with X-ray free-electron lasers depends crucially on algorithms that merge large numbers of weak diffraction patterns despite missing measurements of parameters such as particle orientations. The…

Computational Physics · Physics 2021-08-24 B. R. Mobley , K. E. Schmidt , J. P. Chen , R. A. Kirian

A study is made of the saturation mechanism of a single superradiant spike of radiation in a Free Electron Laser. A one-dimensional (1D) computer model is developed using the Puffin, un-averaged FEL simulation code, which allows…

Accelerator Physics · Physics 2024-02-20 Pornthep Pongchalee , Brian W. J. McNeil

Extended free energy Lagrangians are proposed for first principles molecular dynamics simulations at finite electronic temperatures for plane-wave pseudopotential and local orbital density matrix based calculations. Thanks to the extended…

Chemical Physics · Physics 2011-11-02 Anders M. N. Niklasson , Peter Steneteg , Nicolas Bock

Hyperspectral imagery collected from airborne or satellite sources inevitably suffers from spectral variability, making it difficult for spectral unmixing to accurately estimate abundance maps. The classical unmixing model, the linear…

Computer Vision and Pattern Recognition · Computer Science 2019-06-25 Danfeng Hong , Naoto Yokoya , Jocelyn Chanussot , Xiao Xiang Zhu

All-electron calculations play an important role in density functional theory, in which improving computational efficiency is one of the most needed and challenging tasks. In the model formulations, both nonlinear eigenvalue problem and…

Computational Physics · Physics 2020-07-29 Bin Gao , Guanghui Hu , Yang Kuang , Xin Liu

An efficient numerical algorithm for the laser driven multi-level ionization of high-atomic-number gases is proposed and implemented in an electromagnetic particle-in-cell code SPACE. The algorithm is based on analytical solutions to the…

Plasma Physics · Physics 2022-02-23 Aiqi Cheng , Roman Samulyak

A robust method to handle vacuum and near vacuum regions in hybrid simulations for space and astrophysical plasmas is presented. The conventional hybrid simulation model dealing with kinetic ions and a massless charge-neutralizing electron…

Plasma Physics · Physics 2015-06-22 Takanobu Amano , Katsuaki Higashimori , Keisuke Shirakawa

Miniaturized optical resonators with spatial dimensions of the order of the wavelength of the trapped light offer prospects for a variety of new applications like quantum processing or construction of meta-materials. Light propagation in…

Computational Physics · Physics 2009-05-28 L. Zschiedrich , S. Burger , B. Kettner , F. Schmidt

We introduce an approach for performing spectrally resolved electron microscopy without the need for an electron spectrometer. The method involves an electron beam prepared as a coherent superposition of multiple paths, one of which passes…

Materials Science · Physics 2025-04-24 F. Javier García de Abajo , Cruz I. Velasco

High-intensity, ultrashort, fully coherent X-ray pulses hold great potential for advancing spectroscopic techniques to unprecedented levels. Here, we propose a novel scheme for generating high-brightness and femtosecond-scale soft X-ray…

Accelerator Physics · Physics 2023-06-30 Hanxiang Yang , Jiawei Yan , Haixiao Deng

This paper is devoted to numerical simulation of a charged particle beam submitted to a strong oscillating electric field. For that, we consider a two-scale numerical approach as follows: we first recall the two-scale model which is…

Numerical Analysis · Mathematics 2008-12-22 Alexandre Mouton

Using harmonic emission from circularly polarized undulator is a procedure that is normally employed on synchrotron beamlines in order to extend the covered spectral range. A similar capability is likewise beneficial for next generation…

Optics · Physics 2015-05-28 E. Allaria , G. De Ninno , G. Geloni , C. Spezzani

Many integral equation-based methods are available for problems of time-harmonic electromagnetic scattering from perfect electric conductors. Among the many challenges that arise in such calculations are the avoidance of spurious…

Numerical Analysis · Mathematics 2025-07-17 Felipe Vico , Leslie Greengard , Michael O'Neil , Manas Rachh

Several theories of beyond-the-standard-model physics predict light scalars that couple to fermions. By extending classical electrodynamics to include an electron-scalar coupling, we calculate the nonlinear Thomson scattering of light…

High Energy Physics - Phenomenology · Physics 2019-03-06 Barry M. Dillon , B. King

Free-electron lasers (FELs) operate at wavelengths from millimeter waves through hard x-rays. At x-ray wavelengths, FELs typically rely on self-amplified spontaneous emission (SASE). Typical SASE emission contains multiple temporal "spikes"…

This paper presents a grid-free simulation algorithm for the fully three-dimensional Vlasov--Poisson system for collisionless electron plasmas. We employ a standard particle method for the numerical approximation of the distribution…

Numerical Analysis · Mathematics 2020-03-06 Torsten Keßler , Sergej Rjasanow , Steffen Weißer