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Bienvenue - Laboratoire Jacques-Louis Lions




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5 postes ATER en mathématiques à Sorbonne Université
date limite le 5 avril à 16h
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Chiffres clefs

189 personnes travaillent au LJLL

90 permanents

82 chercheurs et enseignants-chercheurs permanents

8 ingénieurs, techniciens et personnels administratifs

99 personnels non permanents

73 doctorants

14 post-doc et ATER

12 émérites et collaborateurs bénévoles


Chiffres mars 2019


2011-GdT ITER - Y. Fischer

 Intervention de Yannick Fischer


Approximation methods for inverse elliptic problems and applications to tokamaks


This talk is concerned with the Cauchy problem which consists in
recovering Dirichlet and Neumann data on a part of the boundary of a
bounded open planar domain from their knowledge on the complementary
part. The unknown quantity is governed by a real elliptic equation with
a smooth diffusion coefficent.
The first part of this talk deals with the fact that the inverse problem
for elliptic diffusion equation we have in mind may be expressed as a
best approximation problem under constraint for the complex conjugated
Beltrami equation. Such a technique has already proved its relevance for
harmonic identification of linear control systems from partial frequency
Another important practical motivation comes from plasma confinement in
tokamak. A constructive method supported by the use of an appropriate
basis of functions is proposed and gives rise to a robust algorithm for
identifying the plasma shape. Some numerical simulations illustrates the
efficiency of the method.