PIC SIMULATION OF THE SHEATH EVOLUTION PROCESS IN THE PARALLEL PLATE PLASMA

In order to describe in detail the information and evolution of sheath during plasma formation，the PIC model of internal plasma flow in an equal plate is established.On the premise of considering the two electron emission from the wall，a series of parameters such as electric filed intensity，electron density，ion density and electric potential are obtained at the inner and boundary of the plate plasma at the beginning of the discharge until the discharge is stable.The influence of two electron emission coefficient on sheath thickness was analyzed.Simulation results show that：the internal potential of an equal plate is higher than that at the boundary，the strength of the electric filed in the middle is zero，and the electron density is approximately equal to the ion density.At the boundary，the electron density is slightly lower than the ion density，having an approximate positive electric field distribution，its direction is directed to the border.There is obvious sheath at the plasma boundary.