Molecular Dynamics Simulation of the Sputtering of Graphite due to Bombardment With Deuterium and Tritium in Fusion Environment

The sputtering of graphite due to the bombardment of hydrogen isotopes is one of the critical issues in successfully using graphite in the fusion environment. In this work, we use molecular dynamics method to simulate the sputtering by using the LAMMPS. Calculation results show that the peak values of the sputtering yield are located between 25 eV to 50 eV. After the energy of 25 eV, the higher incident energy cause the lower carbon sputtering yield. The temperature which is most likely to sputter is about 800 K for hydrogen, deuterium and tritium. Before the 800 K, the sputtering rates increase when the temperature increase. After the 800 K, they decrease with the temperature increase. Under the same temperature and energy, the sputtering rate of tritium is bigger than that of deuterium, the sputtering rate of deuterium is bigger than that of hydrogen.