Abstract:  For the electrostatic shielding effect, the electric field inside the metal shell is not affected by that outside the shell whether the metal shell is grounded or not. However, it cannot be obtained directly from Gauss theorem that the electric field outside the shell does not affect the electric field at any position inside the shell. In this paper, the electrostatic shielding effect is proved strictly by the uniqueness theorem of electrostatic field. In addition, the electrostatic shielding effect is further verified by numerical simulation. For example, the electric potential of the metal shell changes with the external electric field, which results in the change of the overall electric potential inside the shell while the electric field does not change. Finally, the distribution of the induced charge in the grounded metal shell is numerically calculated, and a large surface density of charge is generated when the metal tip is near the charged objects.

Key words: electrostatic shielding, uniqueness theorem, induced charge