Optimizing the Parameters of a 12-Cavity Rising-Sun Relativistic Magnetron With Single-Stepped Cavities for π -Mode Operation

摘要

We investigated the use of single-stepped cavities instead of typical tapered cavities in an A6 magnetron with diffraction output (MDO) and a 12-cavity MDO through particlein-cell (PIC) simulations using MAGIC [1] and UNIPIC [2] in our earlier publications. The interaction space, where the charged particles interact with the induced RF waves, was increased by replacing tapered cavities with single-stepped cavities in a 12-cavity rising-sun relativistic magnetron with diffraction output (RMDO) that the electronic efficiency of π-mode generation in a 12-cavity rising-sun RMDO with singlestepped cavities driven by a transparent cathode [6] with gigawatt output power level can be as high as 83% for α = 12.5°, 79% for α = 17.5°, and 82% for α = 18.2° at β = 32°, where α is the angle between the inner wall and the z-axis, and β is the angle between the outer wall and the z-axis. When α, the angle between the inner wall and the z-axis, is changed, the depth of single-stepped cavities was changed. This would lead to the coupling between deep cavities and shallow cavities in the 12-cavity rising-sun MDO changing too, and which finally results in different frequencies of magnetron operation in the π-mode. As we know, gigawatt nanosecond output power pulse is useful for the nanoradar system, and our PIC simulations found that when a 400-kV voltage pulse of 10-ns duration is applied to a 12-cavity rising-sun MDO driven by a transparent cathode or a solid cathode, the output power of the π-mode can be as high as 1.5 GW. Without loss of generality, for α = 12.5° and β = 32°, the peak efficiency of π-mode generation in a 12-cavity risingsun MDO with single-stepped cavities design is around 82% and occurs for voltage V ~ 400 kV ± 50 kV. This paper describes optimizing the parameters in a 12-cavity rising-sun RMDO for the desired π-mode operation.