Claudia Negulescu

Learn More
An accelerated algorithm for the resolution of the coupled Schrödinger/Poisson system, with open boundary conditions, is presented. This method improves the subband decomposition method (SDM) introduced in [N. Ben Abdallah, E. Polizzi, Subband decomposition approach for the simulation of quantum electron transport in nanostructures, J. Comp. Phys. 202(More)
This paper is devoted to the numerical approximation of a nonlinear temperature balance equation, which describes the heat evolution of a magnetically confined plasma in the edge region of a tokamak. The nonlinearity implies some numerical difficulties, in particular long time behavior, when solved with standard methods. An efficient numerical scheme is(More)
Heat transfer in magnetically confined plasmas is a process characterized by non-linear and extremely high anisotropic diffusion phenomena. Standard numerical methods, successfully employed in the numerical treatment of classical diffusion problems, are generally inefficient, or even prone to break down, when such high anisotropies come into play, leading(More)
An efficient and accurate numerical method is presented for the solution of highly oscillatory differential equations. While standard methods would require a very fine grid to resolve the oscillations, the presented approach uses first an analytic (second order) WKB-type transformation, which filters out the dominant oscillations. The resulting ODE is much(More)
Abstract. In this article we introduce an asymptotic preserving scheme designed to compute the solution of a two dimensional elliptic equation presenting large anisotropies. We focus on an anisotropy aligned with one direction, the dominant part of the elliptic operator being supplemented with Neumann boundary conditions. A new scheme is introduced which(More)
An efficient and accurate numerical method is presented for the solution of highly oscillatory differential equations. While standard methods would require a very fine grid to resolve the oscillations, the presented approach uses first an analytic (second order) WKB-type transformation, which filters out the dominant oscillations. The resulting ODE is much(More)
In this paper, we study an efficient numerical scheme for a strongly anisotropic elliptic problem which arises, for example, in the modeling of magnetized plasma dynamics. A small parameter ε induces the anisotropy of the problem and leads to severe numerical difficulties if the problem is solved with standard methods for the case 0 < ε 1 . An(More)
In this work, a new numerical scheme for the reduced resistive MHD system (RMHD) is presented. Numerical simulations of RMHD are notoriously challenging because of the disparate time-scales, encompassing the Alfvén wave period and the resistive diffusion time, and because of the formation of thin internal layers, especially in the nonlinear phase. The new(More)