T.W.T.-type radiation from a uniformly moving charge in an isotropic plasma environment

The characteristics of the travelling-wave-tube-type radiation produced by a point charge moving with uniform velocity along the axis of an infinite cylindrical cavity of free space in an otherwise unbounded, isotropic, cold and homogeneous plasma are investigated. For sufficiently small radius of the free-space column, the frequency of the emitted radiation is close to the plasma frequency, and the radiated energy is of significant strength and progresses in a direction opposite to that of the motion of the charge.