CONCEPTUALIZATION OF A 95 GHz,- 100 kW CW GYROTRON

Abstract

Gyrotron oscillators (gyromonotrons) are mainly used as high power millimeter wave sources for electron cyclotron resonance heating (ECRH)(28-170 GHz), electron cyclotron current drive (ECCD), stability control and diagnostics of magnetically confined plasmas for generation of energy by controlled thermonuclear fusion. Gy-rotron oscillators are fast wave devices (vvh. > c) that emits coherent radiation at approximately the electron cyclotron frequency or its harmonics. In this work, the design studies of a 95 GHz, 100 kW, CW gyrotron for ECRH&CD/ ECRIS applications are presented. Mode competition and mode selection are care-fully investigated by considering various candidate modes and the TE10,4 is chosen as the operating mode. A conventional cylindrical cavity resonator with weak input and output tapers and parabolic roundings is considered for interaction studies. Self-consistent, both single-mode and time-dependent, calculations are carried out and power and efficiencies are computed for a typical set of beam parameters. In addition, preliminary design of the quasi-optical launcher, RF window, magnetic guidance and beam optic system are presented. Thus, a comprehensive conceptual study is presented which indicates that the operation of such a gyrotron is possible and can give power in excess of 100 kW at > 35% efficiency. A Graphical User. Interface package "GDS V.01" (Gyrotron Design Suit Ver.01) has been carefully studied and upgraded in MATLAB R2006a on HP xw6400 Work-station having 3 GB RAM. This package has been developed based on existing numerical codes for gyrotrons. The software incorporates the mode selection pro-cedure, starting current calculations, gun synthesis (triode type) and design of coils, resonator design and RF—behavior calculations, quasi—optical launcher design, non-linear taper design(raised cosine type) and RF window design. This package can be used to carry out feasibility studies and conceptualization of specific gyrotrons.