Design of a large orbit gyrotron with a permanent magnet system

In this paper, we present results of a conceptual design study of a prospec tive gyro-device with a permanent magnet system and an axis-encircling elec tron beam. Computer-aided electron-optical design of the tube has been perf ormed by the new version of the software package GUN-MIG named GUN-MIG/CUSP . It is based on a self-consistent relativistic physical model and is devel oped as a problem-oriented tool for analysis of electron-optical systems wi th conventional magnetron injection guns (MIG) and electron guns with field reversal (cusp guns), forming axis-encircling beams. Results of numerical experiments predict satisfactory performance of the gun which is expected t o form high-quality axis-encircling electron beams with small ripple and di spersion of the velocities. Parameters of the beams (current, radius, veloc ity ratio, etc.) are appropriate for weakly relativistic harmonic large orb it gyrotron (LOG). The cavity was optimized for excitation of TE41 mode at the fourth harmonic of the cyclotron frequency, The results of this feasibi lity study will be used as a basis for development of a novel LOG with a pe rmanent magnet system. The target parameters of such a prospective device a re frequency of generated microwave radiation about 104GHz, output power ne ar 1kW and efficiency of several percent. (C) 2001 Elsevier Science Ltd. AH rights reserved.