First heat flux estimation in the lower divertor of WEST with embedded thermal measurements

J. Gaspar (1) , Y. Corre (2) , M. Firdaouss (2) , J.L. Gardarein (1) , J. Gerardin (2) , J. P Gunn (2) , M. Houry (2) , Guillaume Laffont (3) , Thierry Loarer (2) , M. Missirlian (2) , Jorge Morales (2) , P. Moreau (2) , C. Pocheau (2) , E. Tsitrone (2)

1 IUSTI - Institut universitaire des systèmes thermiques industriels
2 IRFM - Institut de Recherche sur la Fusion par confinement Magnétique
3 LCFO (CEA, LIST) - Laboratoire Capteurs Fibres Optiques (CEA, LIST)

The present paper deals with the surface heat flux estimation with thermocouples (TC) and fiber Bragg grating (FBG) embedded in the plasma facing components (PFC) of the WEST tokamak. A 2D heat transfer model combined with the conjugate gradient method and the adjoint state is used to estimate the plasma heat flux deposited on the PFC. The plasma heat flux is characterized by the time evolution of its amplitude and spatial shape on the target (heat flux decay length, power spreading in the private flux region and the strike point location). As a first step, five ohmic pulses have been investigated with different magnetic configuration and divertor X-point height varying from 44 to 68 mm from the surface. Despite an outboard shift, the relative displacements of the outer strike point as well as the heat flux decay length derived from the TC/FBG systems are consistent with the magnetic equilibrium reconstruction.

Mots clés: Plasma diagnostic; heat flux decay length; heat flux estimation; embedded thermal measurement; inverse method; Plasma facing component; instrumentation; Fiber Bragg Grating; WEST tokamak

Domaines: Physique des plasmas [physics.plasm-ph]; Thermique [physics.class-ph]

J. Gaspar, Y. Corre, M. Firdaouss, J.L. Gardarein, J. Gerardin, et al.. First heat flux estimation in the lower divertor of WEST with embedded thermal measurements. Fusion Engineering and Design, 2019, 146 part A, pp.757-760. ⟨10.1016/j.fusengdes.2019.01.074⟩. ⟨hal-02050673⟩