Numerical study of foilless diode

Based on the numerical simulation of the foilless diode presented, the following conclusions can be summarized. (1) At finite magnetic field, the effect of the shank emission on the electron beam could not be neglected. Although shank emission increases the beam current, it reduces the beam quality, which could be solved by increasing the applied magnetic field and decreasing the radial electric field at the cathode shank. (2) For the diode current, the beam equilibrium model is valid in ultra-relativistic case, while the space-charge-limited model is suitable for relatively low voltage.