Wave-particle interactions in a long traveling wave tube with upgraded helix

Autor(es)

de Sousa, M. C. ^{[1, 2]} ; Doveil, F. ^[2] ; Elskens, Y. ^[2] ; Caldas, I. L. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Fis, BR-05508090 Sao Paulo - Brazil

^[2] Aix Marseille Univ, CNRS, UMR 7345 PIIM, F-13397 Marseille - France

• Tipo de documento: Artigo Científico
• Fonte: Physics of Plasmas; v. 27, n. 9 SEP 2020.
• Citações Web of Science: 0

Resumo

We investigate the interaction of electromagnetic waves and electron beams in a 4 m long traveling wave tube (TWT). The device is specifically designed to simulate beam-plasma experiments without appreciable noise. This TWT presents an upgraded slow wave structure (SWS) that results in more precise measurements and makes new experiments possible. We introduce a theoretical model describing wave propagation through the SWS and validated by the experimental dispersion relation, impedance, and phase and group velocities. We analyze nonlinear effects arising from the beam-wave interaction, such as the modulation of the electron beam and the wave growth and saturation process. When the beam current is low, the wave growth coefficient and saturation amplitude follow the linear theory predictions. However, for high values of current, nonlinear space charge effects become important and these parameters deviate from the linear predictions, tending to a constant value. After saturation, we also observe trapping of the beam electrons, which alters the wave amplitude along the TWT. (AU)

• Processo FAPESP: 15/05186-0 - Bifurcações e controle de caos na interação onda-partícula
• Beneficiário: Meirielen Caetano de Sousa
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 13/01335-6 - Controle de caos na interação Onda-Partícula
• Beneficiário: Meirielen Caetano de Sousa
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado Direto
• Processo FAPESP: 11/20794-6 - Caos em sistemas relativísticos magnetizados: aceleração regular e controle do caos
• Beneficiário: Meirielen Caetano de Sousa
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 18/03211-6 - Dinâmica não linear
• Beneficiário: Iberê Luiz Caldas
• Modalidade de apoio: Auxílio à Pesquisa - Temático