2D simulation of periodic magnetic system with open magnetic rings

Based on the measured values on the axis of the magnetic system of the traveling wave tube(TWT), an axis-symmetrical equivalent model of magnetic ring, whose volume is equal to that of the practical non-axis-symmetrical magnetic ring with a gap, is presented. The magnetic field on-axis of this model including pole shoes on both sides is the same as that of the practical open ring with pole shoes. The computed values of the periodic magnetic system containing the equivalent models by the 2D FEMM are in agreement with the measured results of the real system with open magnetic rings.