Excitation of electromagnetic modes in a dielectricloaded waveguide via cyclotron resonance interaction
Abstract
An analytical treatment of the excitation of electromagnetic modes by an axial electron beam in a cylindrical waveguide partially loaded with a dielectric is presented. Equations describing the mode structure of the waves are obtained in cylindrical geometry. Using appropriate boundary conditions, a dispersion relation is derived in the weakbeam approximation. In addition to the conventional Cerenkov interaction, the slowcyclotron resonance interaction, which involves the coupling of the TM mode of the waveguide with the slow cyclotron beam mode, is also seen to be important. The growth rate of the instability scales as the square root of n(0) (where n(0) is the beam density), decreases with an increase in V(0), and is rather insensitive to the variation in the magnetic field.
 Publication:

IEEE Transactions on Plasma Science
 Pub Date:
 February 1986
 DOI:
 10.1109/TPS.1986.4316493
 Bibcode:
 1986ITPS...14...31J
 Keywords:

 Cyclotron Resonance;
 Electromagnetic Radiation;
 Electron Pumping;
 Traveling Wave Tubes;
 Wave Excitation;
 Waveguides;
 Beam Interactions;
 Dielectrics;
 Resonant Frequencies;
 Electronics and Electrical Engineering