Design of a large-radius high impedance intense current diode based on gradient magnetic field

Abstract

In order to reduce the size of high impedance diodes and magnetic energy consumptions, a high impedance intense current diode is designed in this paper. By reducing the center radius of the cathode and utilizing the gradient magnetic field, the electron beam is emitted in the cathode with a small radius and transmitted in the drift tube with a large radius. The influence of magnetic field distribution on the electron beam transmission is analyzed by particle-in-cell simulation. When the diode voltage is 680 kV, the impedance is 77 Ω, and the cathode radius is 60 mm, the anode radius of the traditional diode is 116 mm and the cathode–anode axial gap is 57 mm. At the same voltage and impedance, the cathode radius of the novel diode is 38 mm, the anode radius is reduced to 80 mm, and the cathode–anode axial gap is shortened to 36 mm. Further application of the novel diode to a relativistic triaxial klystron amplifier device shows that the output power of the novel diode is the same as that of the traditional diode. Through simple quantitative analysis, it is found that the magnetic energy consumption of the novel diode is less than that of the traditional diode. To sum up, the novel diode can achieve good performances in a smaller volume than the traditional diodes.