Study of cathode emission surface defects in relativistic magnetrons

The cathode emission surface (CSD) defect is one of the main reasons for the performance difference in relativistic magnetron multiple pulses operation, but its impact mechanism is unclear. In this work, the kinetics model and the particle in a cell method were used to explain the influence of the emission defect effect. The results indicate that the CSD effect causes deformation of the electron sheath and reduces the current. The emission defects in the azimuthal direction - pi/2 < n phi* < pi/2 region favor the electron bunching. Moreover, the emission defects on the cathode side near the accelerator in the axial direction weaken the axial drift issues. Our work will provide a basis for the large-area cathode design and facilitate the relativistic magnetron experimental analysis.