Full Wave Analysis of Coaxial Gyrotron Cavity With Triangular Corrugations on the Insert

Field analysis of coaxial gyrotron cavity with triangular corrugations on the insert is undertaken using full wave approach. The inclusion of insert offers the advantage of mode selectivity and reduction in voltage depression. The effect of insert can be enhanced by having corrugations on it. Mathematical expressions for eigenvalue and ohmic loss of triangular corrugated coaxial cavity have been derived using full wave approach specifically space harmonics method (SHM). Degeneration of SHM to surface impedance method under specific conditions is also discussed and analyzed. The inclusion of harmonics has a small effect on eigenvalue but the ohmic loss varies significantly. An interaction structure design for 170-GHz, 2-MW coaxial-cavity gyrotron with triangular corrugations on the insert is discussed. Mode competition and ohmic losses for such a structure have also been calculated.