Harmonic {L}angmuir Waves. {III}\@. {V}lasov Simulation,
Umeda, T., Omura Y., Yoon P. H., Gaelzer R., and Matsumoto H.
, Physics of Plasmas, February, Volume 10, Number 2, p.382–391, (2003)
Abstractn/a
Generation of harmonic Langmuir modes during beam–plasma interaction is studied by means of nonlinear theoretical calculations and computer simulations. The present Vlasov simulation of multiple harmonic Langmuir modes (up to 12th harmonics), generalizes the previously available simulations which were restricted to the second harmonic only. The frequency-wave-number spectrum obtained by taking the Fourier transformation of simulated electric field both in time and space shows an excellent agreement with the theoretical nonlinear dispersion relations for harmonic Langmuir waves. The saturated wave amplitude features a quasi-power-law spectrum which reveals that the harmonic generation process may be an integral part of the Langmuir turbulence.
Harmonic {L}angmuir Waves. {II}\@. {T}urbulence Spectrum,
Gaelzer, R., Yoon P. H., Umeda T., Omura Y., and Matsumoto H.
, Physics of Plasmas, February, Volume 10, Number 2, p.373–381, (2003)
Abstractn/a
The Langmuir wave turbulence generated by a beam–plasma interaction has been studied since the early days of plasma physics research. In particular, mechanisms which lead to the quasi-power-law spectrum for Langmuir waves have been investigated, since such a spectrum defines the turbulence characteristics. Meanwhile, the generation of harmonic Langmuir modes during the beam–plasma interaction has been known for quite some time, and yet has not been satisfactorily accounted for thus far. In paper I of this series, nonlinear dispersion relations for these harmonics have been derived. In this paper (paper II), generalized weak turbulence theory which includes multiharmonic Langmuir modes is formulated and the self-consistent particle and wave kinetic equations are solved. The result shows that harmonic Langmuir mode spectra can indeed exhibit a quasi-power-law feature, implying multiscale structure in both frequency and wave number space spanning several orders of magnitude.
Harmonic {L}angmuir Waves. {I}\@. {N}onlinear Dispersion Relation,
Yoon, P. H., Gaelzer R., Umeda T., Omura Y., and Matsumoto H.
, Physics of Plasmas, February, Volume 10, Number 2, p.364–372, (2003)
Abstractn/a
Generation of electrostatic multiple harmonic Langmuir modes during beam–plasma interaction process has been observed in laboratory and spaceborne active experiments, as well as in computer simulation experiments. Despite earlier efforts, such a phenomenon has not been completely characterized both theoretically and in terms of numerical simulations. This paper is a first in a series of three papers in which analytic expressions for harmonic Langmuir mode dispersion relations are derived and compared against the numerical simulation result.
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