Topic/Type: 1.6 Plasma-based devices, Poster

3D Electromagnetic Particle-In-Cell Simulation of Microwave Magnetron

H. Usui1, Y. Uranishi2, T. Mitani2

1 Graduate school of Engineering, Kobe University, Kobe, JAPAN
2 Research Institute for Sustainable Humanosphere, Kyoto University, Uji, JAPAN

The objectives of the current study are to quantitatively analyze the electromagnetic interactions with the electrons drifting around the cathode in the process of the microwave generation in a magnetron by performing three-dimensional (3D) electromagnetic particle-in-cell (PIC) simulations with a realistic model of the internal of a magnetron. For this purpose we have developed a new 3D electromagnetic magnetron simulator.
To simulate the electrons-EM field resonance in a real magnetron, we used the Cartesian coordinate system and modeled the three-dimensional internal space of a magnetron as precisely as possible by using a uniform grid size. We also modeled constant electron emission from the cathode surface located at the center as well as the antenna attached at the top of the magnetron for the output of the generated microwaves. In the simulations, we transformed Maxwell\'s equations into differential form. We advance electromagnetic components by solving Maxwell\'s equations with FDTD (Finite-Difference Time-Domain) method. Positions of electrons are advanced with the field components interpolated to the electrons\' position. The external static magnetic field is along the z axis. Between the cathode and anode, constant voltage is applied. The generated microwaves are emitted out through the antenna. The radiated microwaves are numerically attenuated at the outer boundary of the simulation space. In a test simulation, the obtained magnetron efficiency is approximately 73% which is very close the real magnetron. The obtained power of the magnetron is 2.2kW. These simulation facts guaranteed us that the newly developed simulator can correctly simulate a real magnetron function.