> Well, the charge distributes at the surface such that the electric field at the surface has no component parallel to the surface, but only vertical components; otherwise a current flows until such a distribution is achieved
I agree, but in the presence of external fields, perhaps the charges distributes in non uniform manner in order to have the same potential and all electric field lines perpendicular to the surface.
I made a simple finite element code that calculates the charge distribution and I wondered because I obtained a non uniform charge distribution in the metal plate, perhaps due it is non uniform or perhaps due low resolution.
Perhaps I should increase the speed and resolution by making a multithreaded code or using the graphics card
Today I measured the field by introduction of a small metal plate that I connected to an oscilloscope, but I obtained low voltage levels, perhaps due the 5-7pF load of the scope probe. What method or sensor do you recommend to measure the electric potential?