Modeling ultra-high frequency radiation emission in PIC codes

From the mysterious?ray bursts, which can be studied through the spatiotemporal structure of the radiation we receive, to the creation of sources of x-rays capable of probing nanoscale structures, radiation emission by relativistic charges is a key research field in plasma physics.The processes behind radiation emission in plasmas result from strongly non-linear many body interactions which involve relativistic effects, so they are best modeled through Particle-In-Cell (PIC) simulations. However, capturing this radiation directly in PIC simulations is very challenging due to the large disparity between the temporal and spatial scales associated with such phenomena. Current algorithms only describe radiation processes in the Fourier space (e.g.JRAD [1]), missing the spatiotemporal features of the emitted radiation, which is crucial to many fields, such as super-resolution microscopy [2] and astrophysics [3].info:eu-repo/semantics/publishedVersio

RaDiO: An efficient spatiotemporal radiation diagnostic for particle-in-cell codes

This work describes a novel radiation algorithm designed to capture the three-dimensional, space-time resolved electromagnetic field structure emitted by large ensembles of charged particles. The algorithm retains the full set of degrees of freedom that characterize electromagnetic waves by employing the Liénard-Wiechert fields to retrieve radiation emission. Emitted electric and magnetic fields are deposited in a virtual detector using a temporal interpolation scheme. This feature is essential to accurately predict field amplitudes and preserve the continuous character of radiation emission, even though particle dynamics is known only in a discrete set of temporal steps. Our algorithm retains and accurately captures, by design, full spatial and temporal coherence effects. We demonstrate that our numerical approach recovers well known theoretical radiated spectra in standard scenarios of radiation emission. We show that the algorithm is computationally efficient by computing the full spatiotemporal radiation features of High Harmonic Generation through a plasma mirror in a Particle-In-Cell (PIC) simulation.info:eu-repo/semantics/publishedVersio

Impact of non-linear resonators in periodic structures using a perturbation approach

International audienceThe work describes the wave propagation in a periodic structure formed by a linear spring-mass chain with local Duffing non-linear resonators. The wave propagation of the system is studied using the Floquet-Bloch theorem combined with a perturbation approach to identify the dispersion relations in the nonlinear periodic structure. The theoretical model is benchmarked by a numerical approach based on imposing a wave number on a finite resonant spring-mass system as an initial condition, and then obtaining the corresponding frequency from the chain amplitude in the time domain. The perturbation and the numerical methods are compared to discuss the behaviour of the wave propagation in the non-linear resonators periodic chain considered in this work. The results from the perturbation techniques are also compared with the ones generated through an Harmonic Balance Method previously used in open literature

ASIC para sistemas de medidas ambientales

El circuito integrado que aquí se describe ha sido diseñado con tecnología puramente digital, y tiene como función servir como centro concentrador de datos en estaciones meteorológicas, aunque por su diseño genérico puede ser usado en cualquier otro campo. Su objetivo principal es la adquisición de medidas (condiciones ambientales como velocidad y dirección del viento, tempera-turas, humedades relativas,...) y la generación de señales analógicas y digitales telemandadas procedentes de un canal de radio o de un canal SPI. Esta realización se enmarca dentro del programa GAME y ha sido desarrollada en colaboración con la empresa SAINCO