skip to main content

Title: Effect of ion compensation of the beam space charge on gyrotron operation

In gyrotrons, the coherent radiation of electromagnetic waves takes place when the cyclotron resonance condition between the wave frequency and the electron cyclotron frequency or its harmonic holds. The voltage depression caused by the beam space charge field changes the relativistic cyclotron frequency and, hence, can play an important role in the beam-wave interaction process. In long pulse and continuous-wave regimes, the beam space charge field can be partially compensated by the ions, which appear due to the beam impact ionization of neutral molecules of residual gases in the interaction space. In the present paper, the role of this ion compensation of the beam space charge on the interaction efficiency is analyzed. We also analyze the effect of the electron velocity spread on the limiting currents and discuss some effects restricting the ion-to-beam electron density ratio in the saturation stage. It is shown that the effect of the ion compensation on the voltage depression caused by the beam space charge field can cause significant changes in the efficiency of gyrotron operation and, in some cases, even result in the break of oscillations.
Authors:
;  [1] ;  [2]
  1. Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation)
  2. Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742-3511 (United States)
Publication Date:
OSTI Identifier:
22408356
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 4; Other Information: (c) 2015 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; BEAMS; COHERENT RADIATION; CYCLOTRON FREQUENCY; CYCLOTRON RESONANCE; EFFICIENCY; ELECTRIC POTENTIAL; ELECTRON DENSITY; INTERACTIONS; IONIZATION; MICROWAVE AMPLIFIERS; MOLECULES; RELATIVISTIC RANGE; SPACE CHARGE; VELOCITY