Heat flux distribution and gyro-radius smoothing effect on misaligned CFC tile in the Tore Supra tokamak.

Understanding heat flux deposition processes is essential for the design of the plasma facing component allowing reliable high power steady state plasma operations. Misalignments up to δ = 0.2 mm between two adjacent CFC tiles have been reported on the Toroidal Pump Limiter of Tore Supra. Heat flux impinging the top and leading edge of the protruding tile are characterized with both IR thermographic system and numerical modelling using 2D particle-in-cell simulations that accounts for the Larmor radius smoothing effect of incident ions. Numerical heat loads are coupled with a 2D thermal model of the tile and with a specific sensor correction to simulate spatial-resolution related effects (necessary here since the tile misalignment is smaller than the spatial resolution of the IR system). In the experiment depicted here, with a misalignment smaller than an ion gyro-radius, the Larmor radius smoothing effect is maximum and overheating of the leading edge is reduced by a factor of two. [ABSTRACT FROM AUTHOR]