Incoherent interaction of light with electron-acoustic waves

Nonlinear wave interactions as a model for naturally enhanced ion-acoustic lines in the ionosphere

Incoherent radar scatter from the ionosphere will, for equilibrium conditions, show two symmetric ion-acoustic lines, one for each direction of wave propagation. Many observation, from the EISCAT Svalbard Radar (ESR) for instance, demonstrate that the symmetry of this ion line can be broken, accompanied by an enhanced, nonthermal, level of fluctuations, i.e., Naturally Enhanced Ion-Acoustic Lines (NEIALs). Several models have been proposed for explaining these naturally enhanced lines. Here, we consider one of these, suggesting that decay of electron beam excited Langmuir waves gives rise to e…

Bandwidth effects in stimulated Brillouin scattering driven by partially incoherent light

A generalized Wigner-Moyal statistical theory of radiation is used to obtain a general dispersion relation for Stimulated Brillouin Scattering (SBS) driven by a broadband radiation field with arbitrary statistics. The monochromatic limit is recovered from our general result, reproducing the classic monochromatic dispersion relation. The behavior of the growth rate of the instability as a simultaneous function of the bandwidth of the pump wave, the intensity of the incident field and the wave number of the scattered wave is further explored by numerically solving the dispersion relation. Our re…

电子俘获对均匀等离子体中非相干宽带激光下受激拉曼散射的影响

Impact of electron trapping on stimulated Raman scattering under incoherent broadband laser light in homogeneous plasma

本文研究了均匀等离子体中电子俘获对非相干宽带激光下受激拉曼散射的影响，发现在 Landau 阻尼主导的动力学膨胀区，增加激光带宽对抑制受激拉曼散射效果有限，等离子体波饱和与后向散射水平仍保持高位。

Suppression of stimulated Raman scattering by angularly incoherent light, towards a laser system of incoherence in all dimensions of time, space, and angle

Laser-plasma instability (LPI) is one of the main obstacles in laser-driven inertial confinement fusion (ICF) for achieving predictable and reproducible fusion at high gain. For the first time we have proved analytically and confirmed with three-dimensional particle-in-cell simulations that angular incoherence has additional and much stronger suppression of the instability growth rate than the well-known temporal incoherence and spatial incoherence usually used in ICF studies. For the model used in our calculations, the maximum field ratio between the stimulated Raman scattering and the drivin…

Towards a model of incoherent scatter signal spectra without averaging over sounding runs

This paper offers a model for incoherent scatter signal spectra without averaging the received signal over sounding runs (realizations). The model is based on the existent theory of radio waves single scattering from the medium dielectric permittivity irregularities, and on the existing kinetic theory of the plasma thermal irregularities. The proposed model is obtained for the case of monostatic sounding. The model shows that the main contribution to the received signal is made by ion-acoustic waves caused by certain spatial harmonics of the ions number phase density. The model explains the wi…