Description du sujet de thèse

Liquid Metal Flow for Magnetic Fusion Blanket: Numerical Modeling.

Understanding of the physics and control of thermonuclear fusion reactions has progressed in recent decades, with several fusion reactors being constructed and operated experimentally worldwide. Most explored configurations use a confinement system fueled by a Deuterium-Tritium (DT) plasma mixture. Magnetic confinement is the most advanced strategy for harnessing fusion energy to produce electrical power. In this context, the DT plasma is confined by a strong magnetic field provided by superconducting magnet coils. Plasma activity is subject to instabilities (i.e., edge-localized modes and disruptions) that release significant flows of electrons, neutrons, alpha particles, and heat (thermal and radiative) outwards from the plasma confinement. A nuclear blanket protects the superconducting coils from the adverse effects of plasma activity and interfaces with several other components essential to the machine's operation.
Liquid-metal blanket face-to-plasma components offer an alternative to the most demanding protection challenges. They could withstand heat fluxes without permanent damage, opening the door to entirely new magnetic fusion operating regimes. To realize this potential, innovative technologies must be developed. Liquid lithium surfaces are an innovation that could fulfill the promise of fusion power in electricity generation.

This PhD proposal will address the numerical modeling of liquid metal flowing as part of the blanket protection. This thin layer of metal flow is a promising alternative to protect against possible melting damages that Disruptions and MHD instabilities can cause in fusion devices. The liquid metal blanket will operate according to the principles of magnetohydrodynamics (MHD), which are the same principles that produce the Dynamo effect. The PhD will discuss modeling and numerical challenges associated with the dynamics of a thin layer of metal flow under a strong magnetic field and in a complex geometry.

The first year of the PhD will be devoted to developing a 3D curve Hermite-Bezier Finite element for meshing SOL and fitting with equilibrium and Plasma-Facing Components. The associated theoretical part is already available. Adding numerical applications with "Septic Hermite Bezier" will lead to a scientific paper being submitted to a high-standard international Journal.

The last two years will focus on the numerical modeling of liquid metal flows, using numerical strategies developed in the first year.

References
- A generalised formulation of G-continuous Bezier elements applied to non-linear MHD simulations
SJP Pamela, GTA Huijsmans, M Hoelzl, Jorek Team
Journal of Computational Physics, 2022.
- M Hoelzl, GTA Huijsmans, SJP Pamela, M Becoulet, E Nardon, FJ Artola, B Nkonga, et al. The JOREK non-linear extended MHD code and applications to large-scale instabilities and their control in magnetically confined fusion plasmas NF, 2021.
-On the exploration of innovative concepts for fusion chamber technology.
M.A. Abdou et al. Fusion Engineering and Design, 2001.

- Compact fusion blanket using plasma-facing liquid Li-LiH walls and Pb pebbles.
Victor Prosta, Sabine Ogier-Collin, Francesco A. Volpea, Journal of Nuclear Materials, 2024.

Contexte de travail

MHD Plasma modeling is a significant topic in the Inria project team CASTOR (https://team.inria.fr/castor/) and the Eurofusion project team JOREK (https://www.jorek.eu/). It is also a collaborative research topic with the TIFR-Bangalore Institute in India (https://www.math.tifrbng.res.in/people/praveen).

Contraintes et risques

The candidate should have a strong background in the finite elements approach, Numerical analysis, FORTRAN/C++ programming, and High-Performance Computing (HPC). Some familiarity with plasma physics will also be appreciated.