[NotiAMCA] Post Doc Position INRIA
Victorio Sonzogni
sonzogni en intec.unl.edu.ar
Jue Feb 14 16:55:01 ART 2008
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INRIA-LORRAINE
INRIA 2008 POSTDOCTORAL FELLOWSHIP PROPOSAL
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City : Nancy
Title of Research Project: Domain decomposition for full wave simulation
of cold plasma.
INRIA team in which the research would be effected: CALVI
Fellowship supervisor: Jean Roche
Description of Research:
Waves at a frequency close to the lower hybrid (LH) resonance are widely
used in tokamaks for current drive. Modelling of LH waves is usually
carried out using Ray-tracing code for computing the LH waves
propagation and absorption. First “full wave” simulations based on
spectral techniques have shown different results in comparison to RT
model and inconistencies still remain.
The aim of this post doctoral fellowship is to develop a domain
decomposition method for the full-wave simulation of electromagnetic
wave propagation in plasma. This work is a collaboration between the
INRIA team CALVI and the CEA Cadarache(ITER project).
The full-wave method allows us to study the electromagnetic wave
propagation in cold plasma and the"whistler" modes for a frequency near
the lower-hybrid frequency.
In the full wave simulation of wave propagation consider in this project
we study a time harmonic formulation. In this formulation we solve the
governing equation for the electric field.
The domain considered is as near as possible of the cavity fill by a
tokomak plasma. Toroidal coordinates are introduced.
In our approach we consider Fourier decomposition in the angular
coordinate to obtain stationary Maxwell equations in a cross-section of
the tokamak cavity.
To consider finite element numerical method widely used to approximate
the solution of this type of problems we introduce a mixed augmented
variational (weak) formulation taking account the divergence constraint
and natural boundary conditions (Costabel, Ciarlet Jr., Assous, Degond
et al.). An evolution of this method due to Costabel and al. allows us
to consider the anisotropic case.
A code was developed in the total domain case following these ideas in
the team CALVI
The analysis of the weak formulation of our problem with a heterogeneous
behaviour of the conductivity tensor presents some difficulties. We
propose a domain decomposition to overcome this anisotropy.
The next objective is to develop the domain decomposition code, when we
consider the mixed augmented formulation on each sub domains.
It's a non trivial work to identify the interface condition between sub
domains. The postdoctoral fellow will first study interface conditions,
a beginnig point for this research will be the papers of Alonso and
Valli, Quarteroni and Valli, Collino, Ghanemi and Joly.
The domain decomposition must answer to two priorities. The first one is
to take account of the anisotropy of the problem because of the magnetic
field, with stiff behaviour of densities and gradients. We want to be
able to adapt finite element discretization in each sub domains.
The second priority is to adapt the algorithm and the code to parallel
computers. In that case we will be able to consider fine discretization
and compare the results to ray-tracing ones.
Desired profile of candidate:
Ph. D. in Mathematics, Numerical analysis speciality, with good
experience in numerical resolution of PDE's, scientific computation,
and possible knowledge in domain decomposition or Ph.D in Physics,
possibly a specialization in Plasma Physics with a good knowledge of
scientific computation.
Contact: Jean Roche ,
IECN, Université Henri Poincaré
BP 239-54506 Vandoeuvre les Nancy
roche en iecn.u-nancy.fr
Ph. : (33) 3 83 68 45 82
http://www-math.u-strasbg.fr/calvi/
PLEASE Apply at :
http://www.inria.fr/travailler/opportunites/postdoc/postdoc.en.html
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