Size Effect And Numerical Simulation Of Cathode Spots

The size and distribution of the cathode spots play an important role in the anti-erosion capacity and the electron emission ability of electrode materials. Therefore, investigating formation process and factors of the cathode spots is of great significance for the research and development of new electrode materials.In this work, using the ANSYS analysis software the formation mechanism of the cathode spot was simulated. First, author established model and then simulated the formation process of the cathode spots based on W-ThO₂ electrode material. Second, the size effect of the cathode spots was validated, and the results show that the distribution and geometrical properties of cathode spots were completely controlled by the shape and size of ThO₂ particles. With the size ThO₂ decreasing, the electron emission ability of cathode was improved significantly. Finally, the simulation method was applied to research other kinds of electrodes, such as W-La₂O₃ and W-CeO₂ electrodes, and the results show that the simulation method is correct and reasonable thoroughly.From the simulation results, we also noticed that the temperature of surface was lower than the interior temperature, which further confirmed the well-known explosion model of the cathode spots. The simulation result is completely consistent with the experimental result, indicating that the simulation method used in this work is correct and reasonable. Also, this way can be used to improve the design of the electrode materials to shorten the design cycle and improve product design quality. The method provides a reliable new way for researching the electrode materials.