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Title: Electron-optical systems for planar gyrotrons

The methodology of designing an electron-optical system (EOS) that forms sheet helical electron beams (HEBs) for high-power gyrotrons is developed. As an example, we consider the EOS for a 140-GHz gyrotron operated at the first harmonic of the cyclotron frequency with an accelerating voltage of 50 kV, a beam current of 30 A, and a magnetic field compression of 36. A planar geometry of the magnetron-injection gun (MIG) is suggested. The adiabatic theory of MIGs modified for the planar geometry of EOS is used for preliminary estimations of MIG parameters. Numerical simulation of the HEB properties based on the CST STUDIO SUITE 3D code is performed to find the optimal configuration of a planar MIG. The accuracy of the calculated data is discussed. The main factors that affect the HEB quality are considered. It is shown that a sheet HEB with a pitch-factor of 1.3 and velocity spread not exceeding 25%–30% can be formed; this is quite acceptable for high-efficiency operation of modern gyrotrons. Calculation of the beam-wave interaction with the obtained HEB parameters proved that a high output power with a sufficiently good efficiency of about 20% can be reached. Simulations show the feasibility of the experimental implementation of a novelmore » planar EOS and its use in short-wave planar gyrotrons. The developed technique can be used for the study and optimization of planar gyrotrons of different frequency bands and power levels.« less
Authors:
; ; ;  [1] ;  [2] ; ;  [1]
  1. Institute of Applied Physics of the Russian Academy of Sciences, 46 Ul'yanov St., Nizhny Novgorod 603950 (Russian Federation)
  2. (Russian Federation)
Publication Date:
OSTI Identifier:
22252053
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 2; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BEAM CURRENTS; COMPUTERIZED SIMULATION; CYCLOTRON FREQUENCY; ELECTRIC POTENTIAL; ELECTRON BEAMS; ELECTRONS; GEOMETRY; GHZ RANGE; MAGNETIC COMPRESSION; MAGNETIC FIELDS; MAGNETRONS; MICROWAVE AMPLIFIERS; OPTICAL SYSTEMS; PITCHES