Note on boundary conditions in plasma sheath simulations using the particle-in-cell algorithm

We discuss plasma sheath simulations using the particle-in-cell algorithm, focusing on the boundary conditions that have to be applied toward the plasma bulk. We advocate the vanishing-field boundary condition, which strongly dampens the artificial double layer that invariably forms at the plasma-side boundary in collisional plasmas. The results are validated using an analytical modification of the well-known Child's law.