The treatment of the structural materials by the high heat pulsed plasma streams is worth-while direction of plasma technology [1]. One of the most important effect of such treatment – the amorphisation of the metal surface layer – can be achieved at the high degree of both melting and cooling (∼10⁷ K/s) processes. The use of the heat conduction to the bulk of material for the achievement of needed cooling rate imposes the appointed requirements to the heat power on the target surface. The well-founded choice of the modes of such plasma irradiation have to be based on the knowledge of energy flux on the target surface with consideration of the effects of the plasma shielding layer (SL), which is generated from ionised erosion products above the target surface and protects effectively (up to 95%) material against incident power. The significant experience in the study of high heat plasma-material interaction in disruption simulation experiments has allowed to solve this problem. The modes of operation with pulse duration t_p=0.09 ms, irradiation power P_irr=20-100 GW/m² and longitudinal magnetic field B=0-3 T were used on the VIKA facility [2] to study energy flux reached the surface of targets (Al, SS, W, graphite). The visible radiation (400-700 nm) energy flux on the target surface and absorbed energy were studied for this aim. The radiation flux was transported to analysing setup by means of thin (1 mm) quartz fiber inserted into the hole in the sample. The optical tract was calibrated by means of certificated tungsten lamp. The measured values of the specific energy of visible radiation from SL on the target surface can be characterized by the level Q_R∼50 kJ/m² for irradiation power P_irr∼20 GW/m² and the absence of the magnetic field and increases up to Q_R∼300 kJ/m² at max. irradiation power and B=3 T. The total energy flux on the targets surface was identified with the measured values of the specific energy absorbed by the samples during irradiation. The linear growth of the absorbed energy with the rise of irradiation power was observed. The level of absorbed energy Q_abs∼100 kJ/m² sufficient for the melting of the surface layer of most structural metals can be achieved at irradiation power flux P_irr∼30 GW/m². The values of absorbed energy depends feebly on the material and magnetic field values. Experimental data are in the good agreement with numerical modelling results. It is shown that visible radiation power flux from high density (n_e∼10²⁴ m^-3) low temperature (T_e∼1-3 eV) SL determines in a considerable extent the energy flux reached the target surface.

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