Trajectories of electrons in a coupled-cavity TWT with ppm focusing are plotted in both

and

views. Plots are given for magnetic fields from 1.0 to 1.9 times the Brillouin field, and for small signal and saturated RF conditions. It is shown that a suitably programmed field can control the beam entry problem and minimize the RF debunching, while significantly reducing the beam exit angle. The computer program is briefly described.