The local topography of the crater makes permanently shadowed craters (PSCs) over Moon electrically complex. The plasma environment in PSCs is generally characterized by diffused solar wind (SW) plasma. Its dynamics splits the crater into two distinct plasma regions, viz., electron rich region (ERR) and quasineutral region, which essentially describes the electric potential distribution on the crater's surface. Herein, we discuss the electrostatic surface charging of PSCs and illustrate that the fine particles overlying the crater surface significantly contribute to establishing a finite electric potential on the crater surface. We depict that these fine particles act as efficient field emission centers generating electrons via quantum field tunneling and suffice in countering the diffused SW charging flux, establishing steady state charging equilibrium over the crater's surface.
