Dust charging under surface electron emission

Summary form only given. In this work, the effect of surface-emitted secondary electrons on the charge and potential of a dust particle immersed in plasma has been studied by means of a 1D radial Particle-in-Cell (PIC)¹ numerical simulation. The processes of photo-electron and secondary electron emission from the particle surface as a function of primary electron temperature have been taken into account. Results show that a transition from negative to positive dust charge/potential takes place, and that the transition regime is characterized by a nonmonotonic behavior of the electric potential around the particle².In the case of photoelectric emission, the dust charge and potential are monotonic decreasing functions of the primary electron temperature, while in the case of emission induced by primary electrons a minimum charge/potential is reached before they grow towards positive values. In no case multiple dust charge states3 have been observed due to the presence of the potential well attached to the particle surface.