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In this paper, we present the RF behavior of conventional cylindrical interaction cavity for 240 GHz, 1 MW gyrotron for futuristic plasma fusion reactors. Very high-order TE mode is searched for this gyrotron to minimize the Ohmic wall loading at the interaction cavity. The mode selection process is carried out rigorously to analyze the mode competition and design feasibility. The cold cavity analysis and beam-wave interaction computation are carried out to finalize the cavity design. The detail parametric analyses for interaction cavity are performed in terms of mode stability, interaction efficiency and frequency. In addition, the design of triode type magnetron injection gun is also discussed. The electron beam parameters such as velocity ratio and velocity spread are optimized as per the requirement at interaction cavity. The design studies presented here confirm the realization of CW, 1 MW power at 240 GHz frequency at TE mode. [ABSTRACT FROM AUTHOR]

Highlights: [•] Design of triple frequency MW gyrotron. [•] The mode selection process for three frequency operation of MW gyrotron. [•] Design of magnetically tunable magnetron injection gun. [•] CVD diamond window design for triple frequency operation of gyrotron. [Copyright &y& Elsevier]

This paper presents the design of 28 GHz, 200 kW gyrotron for Indian TOKAMAK system. The paper reports the designs of interaction cavity, magnetron injection gun and RF window. EGUN code is used for the optimization of electron gun parameters. TE03 mode is selected as the operating mode by using the in-house developed code GCOMS. The simulation and optimization of the cavity parameters are carried out by using the Particle-in-cell, three dimensional (3-D)-electromagnetic simulation code MAGIC. The output power more than 250 kW is achieved. [ABSTRACT FROM AUTHOR]

A triode magnetron injection gun (MIG) is designed for a 1-MW 170-GHz gyrotron, which will be used in an electron cyclotron resonance heating system for the International Thermonuclear Experimental Reactor. The initial design of MIG is performed by using the in-house code MIGSYN. For the electron-beam emission and propagation, the 2-D code EGUN is implemented. The transverse-to-axial velocity ratio \alpha is 1.37, and the transverse velocity spread less than 4% is realized. The results are also validated against two other 2-D and 3-D codes, i.e., TRAK and CST-Particle Studio, respectively, which are in close agreement. From the fabrication and operation point of view, the parametric analysis and misalignment study of electron beam are also performed. [ABSTRACT FROM PUBLISHER]

The gyrotron that operates with a double electron beam is designed and presented. The design of a 42-GHz 200-kW gyrotron at \TE03 mode has been done and presented elsewhere. To enhance the RF power without losing the interaction efficiency of the 42-GHz gyrotron, double electron beams are launched into the cavity. The beam–wave interaction calculations and power and frequency growth estimation are performed and compared with the single-beam operation results. In the design of the gyrotron, in-house developed codes, GCOMS, MIGSYN, and MIGANS, as well as commercially available codes MAGIC and EGUN are used. The results show that more than 400 kW of power is not possible by single-beam operation while the double-beam operation shows this amount of power with the same mode. To achieve the double electron beams of the desired parameters at the cavity region, the double-beam magnetron injection gun (MIG) is designed. The results of the interaction cavity and MIG show the feasibility of the double-beam gyrotron for high-power and high-efficiency operation. [ABSTRACT FROM PUBLISHER]