Methods and Results of Measurements the Heat–Plasma Flux Density at the Sample in PLM and PLM-M Devices

We describe the techniques and results of measurements of the thermal density of the plasma flux to the test materials in experiments on controlled nuclear fusion. The heat flux has been measured using three different methods: based on the Fourier law (temperature difference in the line of thermocouples in the bulk of the sample), the Stefan–Boltzmann law of radiation (for high temperatures on the surface facing the plasma), and from the temperature difference and the cooling fluid flow rate at the inlet and outlet of the sample cooling system. Experimental values have been obtained for the coefficient of heat-transfer from the helium plasma to the tungsten sample surface.