Theoretical analysis of collective effects in traveling wave tubes

Summary form only given. Self-consistent field theories of traveling wave tubes have been developed based upon both sheath and tape helix models. In both cases, the helix is assumed to be surrounded by a conducting wall. The transverse motion of the electron beam is assumed to be suppressed by a strong magnetic field for the sheath helix, but not for the tape helix, in which the beam dynamics is treated for arbitrary fields exceeding that required for Brillouin flow. Determinantal dispersion equations are derived for both models based upon the solution of the Maxwell-fluid equations subject to the boundary conditions imposed by the beam, helix, and wall.