Surface roughness effects on plasma near a divertor plate and local impact angle

Highlights: • A 2d3v PIC code is used to investigate the distributions of plasma sheath and local impact angle on rough surfaces. • The local impact angle distributions of plasma ions D⁺ for different plasma temperature are almost the same. • The variation of the electric potential for different valley widths is due to the change of rough surface topography. - Abstract: The impact of rough surface topography on the electric potential and electric field is generally neglected due to the small scale of surface roughness compared to the width of the plasma sheath. However, the distributions of the electric potential and field on rough surfaces are expected to influence the characteristics of edge plasma and the local impact angle. The distributions of plasma sheath and local impact angle on rough surfaces are investigated by a two dimension-in-space and three dimension-in-velocity (2d3v) Particle-In-Cell (PIC) code. The influences of the plasma temperature andsurface morphology on the plasma sheath, local impact angle and resulting physical sputtering yield on rough surfaces are investigated.