A Molecular Dynamics Study on the Dust-Plasma/Wall Interactions in the EAST Tokamak

The interactions between the W nano-dust and deuterium plasma at different lo- cations of the EAST tokamak are simulated using a molecular dynamics code. It is shown that nano-dust particles, with the radius, Rd, ~5 nm, can exist for at least several nano-seconds under the interactions from the ions without being ablated in some specific places of the tokamak edge plasma, while those with Rd ≥~25 nm may be ablated if the plasma temperature T~ 50 eV and density n~10^19 m-3. In addition, the collisions of tungsten nano-dust grains with a tungsten wall at 100 m/s or I000 m/s impinging speeds are simulated. It is demonstrated that the dust will stick to the wall, and the collision will not cause substantial damage to the wall, but it may be able to cause partial destruction of the dust grains themselves depending on their incident speeds.