Abstract
The experimental study of radial profiles of parallel heat flux in the scrape-off layer (SOL) of the COMPASS tokamak shows a systematic discrepancy between medium (MWIR) and long (LWIR) wavelength infrared (IR) thermographic measurements. Significant temperature and heat flux overestimation is observed in the MWIR range, whilst the LWIR range is almost not affected.
It is assumed to be caused by a presence of dust particles creating sub-pixel sized micro hot-spots. Significant inhomogeneity of the surface conditions across the limiter is observed, resulting in local disturbance of the derived heat flux profiles (decay length variation up to about few tens of percent).
Influence of the inhomogeneously distributed micro hot-spots is suppressed using correction factors (the heat transmission coefficient α) for each pixel separately in the heat flux calculation. Procedure of the α coefficient estimation is described.