Heat flux mitigation characteristics in the radiative divertors with multi-peaks of heat flux in the large helical device

Abstract In this study, the effects of impurity seeding on the one- and two-dimensional heat flux profiles of the large helical device divertor with a multi-peaks of heat flux were investigated, focusing on the heat-flux-reduction characteristics at the two peaks. The divertor heat flux profile was reconstructed using finite element analysis based on the temperature distribution measured via infrared thermography. The divertor heat flux profiles were calculated using the EMC3-EIRENE code considering the impurity seeding. In general, the calculated results were consistent with the experimental observations, including the heat flux value and reduction via impurity seeding. The reduction in the divertor heat flux due to impurity seeding was almost similar at different heat flux peaks and exhibited little dependence on the heating power variance. The difference between the low- and high-heating-power cases is discussed by tracing the magnetic field lines from the divertor plate and considering the penetration depth of the impurity particles into the scrape-off layer plasma.