RUDI GAELZER
Departamento de Física - Instituto de Física - Universidade Federal do Rio Grande do Sul
Av. Bento Gonçalves, 9500 - Caixa Postal 15051 - 91501-970 - Porto Alegre-RS - Sala N206 (Prédio 43134) (rudi.gaelzer@ufrgs.br) (email)
Av. Bento Gonçalves, 9500 - Caixa Postal 15051 - 91501-970 - Porto Alegre-RS - Sala N206 (Prédio 43134) (rudi.gaelzer@ufrgs.br) (email)
This article demonstrates the generation of enhanced ion-acoustic waves by beam-plasma instability in a density cavity. The self-consistent equations of weak turbulence theory that include quasi-linear, decay, and scattering processes as well as convective and dispersive effects are numerically solved for a one-dimensional density cavity. It is shown that significant enhancements of ion-acoustic waves occur in the presence of counterstreaming electron beams and that the enhanced ion-acoustic waves are initially localized near the center of the density cavity at large wavelengths. Later in the evolution, the enhancement in the spectrum of ion-acoustic waves spreads out toward the edges of the cavity, with a shift to smaller wavelengths, while the enhancement near the center of the cavity tends to decrease in magnitude. The significance of the present findings is discussed.
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