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Information × Registration Number 0209U010251, 0107U006286 , R & D reports Title Investigation of influence of background plasma on efficiency of high-power gyrotrons for thermonuclear fusion applications popup.stage_title Head Shcherbinin Vitaliy Igorovych, Registration Date 20-10-2009 Organization National Science Center "Kharkiv Institute of Physics and Technology popup.description2 The study is devoted to theoretical investigations of parasitic plasma influence on high-performance generation of high-power gyrotrons for thermonuclear fusion applications. Plasma inevitably appears in cavities of these gyrotrons due to impact ionization of background gas by electron beam. Plasma is a dielectric medium that alters electromagnetic properties of gyrotron cavity. In particular, eigenfrequencies of the cavity decrease under the influence of plasma. As a result, for given gyration frequency of beam electrons the nature of resonance between gyrating beam and cavity eigenmodes can be changed. In addition, parasitic plasma modifies eigenfields distribution in transverse cross-section of gyrotron cavity. Thereby, plasma reduces coupling coefficients between cavity modes and electron beam and diminishes effective force of their fields on electrons. In this study the theory of gyrotron has been developed taking into account the modification of cavity frequency spectrum and beam-wave coupling coefficients under the influence of parasitic plasma inside the cavity. The theory includes three main sections. In first section the linear theory of beam interaction with the eigenmodes of plasma-filled cavity has been developed and plasma influence on self-excitation conditions for competing cavity modes has been investigated. In second section the nonlinear stationary theory of plasma-filled gyrotron has been developed in single-mode approximation and plasma influence on oscillation efficiency for operating and some parasitic has been considered. The third section is devoted to nonlinear non-stationary multimode theory of gyrotron with plasma-filled cavity. Therein plasma influence on mode competition and establishment of high-performance single-mode generation regime for gyrotron operating mode has been investigated. On basis of obtained results recommendations has been made that allow optimized gyrotron operation parameters and increase efficiency and power of gyrotrons in plasma heating systems for thermonuclear fusion machines. Product Description popup.authors popup.nrat_date 2020-04-02 Close