Non-thermal effect on collision cascade of tungsten

Abstract

The intense electronic excitations in materials can trigger a series of non-thermal effects, seriously affecting the physical properties of materials. However, the electronic effects on collision cascade of tungsten (W) plasma-facing material in fusion reactors remains unclear. Based on the tight-binding theory, the non-thermal effects on the collision cascade of W material are extensively studied. Our results show that the non-thermal effect arising from intense electronic excitations induces substantial increase in the sputtering yield, as well as in the number of point defects during collision cascade in W slabs. Analysis shows that the observed phenomena are closely related to the deterioration of system’s stability under intense electronic excitations, since high electronic temperature results in the weakness of bonding strength among W atoms. Our work highlights the importance of electronic excitation effects in evaluating the resistance of W material to radiation damage when subjected to intense irradiation fields in fusion reactors.