Title :
Effect of geometric azimuthal asymmetries of PPM stack on electron beam characteristics [TWTs]
Author_Institution :
NASA Glenn Res. Center, Analex Corp., Cleveland, OH, USA
fDate :
1/1/2001 12:00:00 AM
Abstract :
A three-dimensional (3-D) beam optics model has been developed using the electromagnetic particle-in-cell (PIC) code MAFIA. The model includes an electron beam with initial transverse velocity distribution focused by a periodic permanent magnet (PPM) stack. All components of the model are simulated in three dimensions, allowing several azimuthally asymmetric traveling wave tube (TWT) characteristics to be investigated for the first time. These include C-magnets, shunts and magnet misalignment and their effects on electron beam behavior. The development of the model is presented and 3-D TWT electron beam characteristics are compared in the absence of and under the influence of the azimuthally asymmetric characteristics described
Keywords :
digital simulation; electron optics; permanent magnets; travelling wave tubes; C-magnets; MAFIA; PPM stack; beam optics model; electromagnetic particle-in-cell code; electron beam behavior; electron beam characteristics; geometric azimuthal asymmetries; initial transverse velocity distribution; magnet misalignment; periodic permanent magnet; shunts; traveling wave tube; Circuits; Electron beams; Electron optics; Integrated optics; Magnetic flux; Magnetostatics; Optical beams; Optical scattering; Permanent magnets; Solid modeling;
Journal_Title :
Electron Devices, IEEE Transactions on
