AVIS DE SOUTENANCE
Monsieur David MOIRAF
« ED353 Sciences pour l’Ingénieur » : spécialité « Mécanique, Physique, Micro et Nanoélectronique »
Soutiendra publiquement ses travaux de thèse intitulés :
« Addressing the power exhaust challenge in tokamaks with double-null configurations »
dirigés par Dr. Guido CIRAOLO et co-encadrés par Dr. Nicolas FEDORCZAK
Soutenance prévue le jeudi 27 novembre 2025 à 14h00
Lieu : IRFM – Salle René Gravier – Centre de Cadarache 13115 Saint Paul Lez Durance
Et par Skype (voir lien ci-dessous)
Composition du jury :
| Dr. Eleonora VIEZZER | University of Seville, Spain | Rapporteure |
| Dr. Hyung-Ho LEE | KFE, Republic of Korea | Rapporteur |
| Dr. Yannick MARANDET | CNRS PIIM, France | Président du jury |
| Dr. Laure VERMARE | CNRS LPP, France | Examinateur |
| Dr. Paolo INNOCENTE | CNR ISTP, Italy | Examinateur |
| Dr. Kevin VERHAEGH | TU/e, Netherlands | Examinateur |
| Dr. Guido CIRAOLO | CEA IRFM, France | Directeur de thèse |
| Dr. Nicolas FEDORCZAK | CEA IRFM, France | Co-directeur de thèse |
| Dr. Jorge MORALES | CEA IRFM, France | Membre invité |
Keywords :
Fusion, Tokamak, Plasma-Wall Interaction, Double-null, Fluxes, Divertor
Abstract :
This thesis addresses the challenge of power exhaust in tokamaks, a major obstacle to making nuclear fusion a sustainable energy source. DEMO-scale devices are expected to expose divertor targets to heat fluxes of about 77 MW/m², far exceeding the material limits of ~5 MW/m². To mitigate this, we investigate the double-null configuration as an alternative to the conventional single-null configuration. This symmetrical magnetic equilibrium changes the distribution of exhaust power and share it across two divertors. Using experiments on three European tokamaks (WEST in France, TCV in Switzerland, and MAST-U in the UK), we show that the double-null can reduce peak heat loads and can lower thresholds for accessing dissipative divertor regimes. However, the double-null also comes with new challenges: it requires more precise magnetic control and presents a narrower operational range in term of plasma density or impurity seeding. Altogether, the results provide quantitative insights and reduced models demonstrating that the double-null offers a credible path to mitigating power exhaust, and can help guide the design of future fusion power plants.
………………………………………………………………………………………………………………………..