Objetivo Gyrotrons produce CW and long-pulsed mm-wave radiation with unmatched power level and, therefore, are extensively applied for plasma fusion electron cyclotron resonance heating and current drive and for materials processing. Recent improvements in gyrotron design and fabrication technologies resulted in substantial progress in the output parameters of such devices. But up to now the efficiency of these tubes typically does not exceed 40-50%, and needs to be further enhanced. The usual obstacle phenomenon for such an enhancement is a low-frequency oscillatory process (LFO) developing in the helical electron beam (HEB). In gyrotrons HEBs are used as an active medium for DC to RF energy conversion. These LFOs are caused by electron trapping between the cathode and the gyrotron resonator, were the beam is compressed by the increasing magnetic field. The contribution of LFOs to the electron energy spread provokes a reduction of the gyrotron efficiency. Another possible cause for energy spread growth and efficiency decrease can be associated with a spatial non-uniformity of the HEB, originating, for instance, from non-uniformity of cathode emission. These two factors are usually considered to have the strongest negative influence on the beam quality. Even presently, the available quantitative data on their effect are absolutely insufficient. So, acceptable methods for suppression or neutralization of such features have to be developed.The present project includes studies of mechanisms of the influence of non-uniformity and LOFs of an annular electron beam on its quality and investigation of the ways of gyrotron efficiency enhancement through suppression of parasitic oscillations and reduction of the negative effect of beam non-uniformity. These principle objectives are planned to be achieved as the result of theoretical and experimental investigations of the influence of these two factors on electron beam energy spread and on overall gyrotron efficiency. Methods for the reduction of the negative effects from these parasitic phenomena will be developed. This work is expected to yield new scientifically valuable data on HEB space charge behavior and information on the ways for efficiency enhancement in high-power gyrotrons. Participating in the work on the project will be recognized scientists from Forschungszentrum Karlsruhe (Germany), Helsinki University of Technology (Finland), Institute of Applied Physics Nizhny Novgorod (Russia), St. Petersburg State Polytechnical University (Russia) and Ioffe Physico-Technical Institute (Russia). Large and supplementary scientific experiences of the participating teams give ground to expect the successful fulfilment of the planned complex investigations. Programa(s) IC-INTAS - International Association for the promotion of cooperation with scientists from the independent states of the former Soviet Union (INTAS), 1993- Tema(s) OPEN - OPEN Call Convocatoria de propuestas Data not available Régimen de financiación Data not available Coordinador Helmholtz-Gemeinschaft Forschungszentrum Karlsruhe Aportación de la UE Sin datos Dirección Hermann-von-Helmholtz-Platz 1 76021 Karlsruhe Alemania Ver en el mapa Enlaces Sitio web Opens in new window Coste total Sin datos Participantes (4) Ordenar alfabéticamente Ordenar por aportación de la UE Ampliar todo Contraer todo Helsinki University of Technology Finlandia Aportación de la UE Sin datos Dirección Rakentajanaukio 4 FIN-02150 Espoo Ver en el mapa Coste total Sin datos Russian Academy of Sciences A.F. Ioffe Physico-Technical Institute RAS Rusia Aportación de la UE Sin datos Dirección Polytechnicheskaja 26 194021 Saint Petersburg Ver en el mapa Coste total Sin datos Russian Academy of Sciences Institute of Applied Physics RAS Rusia Aportación de la UE Sin datos Dirección Ulyanova 46 603950 Nizhny Novgorod Ver en el mapa Coste total Sin datos St. Petersburg State Polytechnical University Rusia Aportación de la UE Sin datos Dirección Polytechnicheskaja 29 195251 Saint Petersburg Ver en el mapa Coste total Sin datos
