An approximate two-dimensional theory of interaction between an electron beam and an electromagnetic wave (noise- and photo-traveling wave tubes)

Processes that occur in a traveling wave tube(TWT) equipped with a photocathode are examined within two-dimensional theory. The impact of noise fluctuations of the beam is studied, and the dependences of the amplifier’s noise factor are obtained. The interaction between an electromagnetic wave with an infinitely thin strip electron beam is described with allowance for a finite focusing magnetic field and the space charge field.