A drift-kinetic Semi-Lagrangian 4D code for ion turbulence simulation

A new code is presented here, named Gyrokinetic SEmi-LAgragian (GYSELA) code, which solves 4D drift-kinetic equations for ion temperature gradient driven turbulence in a cylinder (r, theta, z). The code validation is performed with the slab ITG mode that only depends on the parallel velocity. This code uses a semi-Lagrangian numerical scheme, which exhibits good properties of energy conservation in non-linear regime as well as an accurate description of fine spatial scales. The code has been validated in the linear and non-linear regimes. The GYSELA code is found to be stable over long simulation times (more than 20 times the linear growth rate of the most unstable mode), including for cases with a high resolution mesh (delta r similar to 0.1 Larmor radius, delta z similar to 10 Larmor radius). (c) 2006 Elsevier Inc. All rights reserved

Uncertainty quantification for kinetic models in socio-economic and life sciences

Kinetic equations play a major rule in modeling large systems of interacting particles. Recently the legacy of classical kinetic theory found novel applications in socio-economic and life sciences, where processes characterized by large groups of agents exhibit spontaneous emergence of social structures. Well-known examples are the formation of clusters in opinion dynamics, the appearance of inequalities in wealth distributions, flocking and milling behaviors in swarming models, synchronization phenomena in biological systems and lane formation in pedestrian traffic. The construction of kinetic models describing the above processes, however, has to face the difficulty of the lack of fundamental principles since physical forces are replaced by empirical social forces. These empirical forces are typically constructed with the aim to reproduce qualitatively the observed system behaviors, like the emergence of social structures, and are at best known in terms of statistical information of the modeling parameters. For this reason the presence of random inputs characterizing the parameters uncertainty should be considered as an essential feature in the modeling process. In this survey we introduce several examples of such kinetic models, that are mathematically described by nonlinear Vlasov and Fokker--Planck equations, and present different numerical approaches for uncertainty quantification which preserve the main features of the kinetic solution.Comment: To appear in "Uncertainty Quantification for Hyperbolic and Kinetic Equations

Beam Simulations for IRE and Driver-Status and Strategy

The methods and codes employed in the U.S. Heavy Ion Fusion program to simulate the beams in an Integrated Research Experiments (IRE) facility and a fusion driver are presented in overview. A new family of models incorporating accelerating module impedance, multi-beam, and self-magnetic effects is described, and initial WARP3d particle simulations of beams using these models are presented. Finally, plans for streamlining the machine-design simulation sequence, and for simulating beam dynamics from the source to the target in a consistent and comprehensive manner, are described

Instability of the time splitting scheme for the one-dimensional and relativistic Vlasov–Maxwell system

International audienceThe Time Splitting Scheme (TSS) has been examined within the context of the one-dimensional (1D) relativistic Vlasov–Maxwell model. In the strongly relativistic regime of the laser–plasma interaction, the TSS cannot be applied to solve the Vlasov equation. We propose a new semi-Lagrangian scheme based on a full 2D advection and study its advantages over the classical Splitting procedure. Details of the underlying integration of the Vlasov equation appear to be important in achieving accurate plasma simulations. Examples are given which are related to the relativistic modulational instability and the self-induced transparency of an ultra-intense electromagnetic pulse in the relativistic regime

Etude mathematiques et implantation numerique du modele de Vlasov-Darwin

SIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : RP 13076 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

High Performance Computing tools for the Integrated Tokamak Modelling project

6 páginas, 6 figuras, 2 tablas.-- European Task Force on Integrated Tokamak Modelling Activity: et al.Fusion Modelling and Simulation are very challenging and the High Performance Computing issues are addressed here. Toolset for jobs launching and scheduling, data communication and visualization have been developed by the EUFORIA project and used with a plasma edge simulation code.This work, supported by the European Communities under the contract of Association between EURATOM and several Associations, was carried out within the framework of the European Fusion Development Agreement. The research leading to these results has also received funding from the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement n◦211804 (EUFORIA).Peer reviewe