Thermionic-field emission of electrons from conical metal points

The electric field in the neighborhood of the tip of conical point exhibits an integrable special feature. Therefore, for calculating the current of thermionic-field emission from a conical point, one has to find (or reasonably estimate) the emission current density, including that at high and, in the limit, infinite fields. It is suggested to solve this problem using, firstly, a numerical method of finding the electric field of a conical point which is capable of correctly describing the feature at the tip and, secondly, a common approach to considering the thermionic, field, and thermionic-field emission of electrons from metal in a wide range of variation of electric field on the surface. It is demonstrated that, at high electric fields, the density of thermionic-field emission current tends to some limiting value, i.e., the effect of saturation of emission current density is observed. The basic reason for this saturation is found. It is demonstrated that the total current of electron emission from a conical point remains finite at not too high values of intensity of external electric field, in spite of the infinite field increasing at the cone tip.