Measurement of Edge Plasma Heat Flux in Heliotron J Using a Thermal Probe

Direct measurement of divertor heat flux is an important task. However, heat flux calibration is often difficult because heat diffusion in sensors takes longer than the discharge duration of present experiments. In this paper, using an unsteady heat conduction model, the heat flux in the Heliotron J edge plasma is measured for the first time. The obtained heat flux value, although it is time averaged, is positively correlated with plasma heating power, more precisely, with plasma internal energy. The angular distribution of heat flux around the probe axis shows a profile shape similar to previously reported probe current distributions.