SGER: Relative Importance of Nonlinearities for Langmuir Turbulence Excited in Ionospheric Heating Experiments

研究人员为电离层高频加热的非线性波-波耦合提供了适用的理论基础，并将该理论应用于Sulzer和Fejer 1994年的实验观测。他们正在推导一组用于研究二次参数不稳定性的一般耦合模式方程，包括推导中的非线性。具体来说,他们:(1)推导耦合模式方程，(2)比较非线性耦合项之间的不同情况，(3)进行实例研究，说明每种非线性的重要性，并对次级参数不稳定性进行系统研究，(4)确定Langmuir波在特定频率范围内的频谱分布，(5)研究参数激发离子声波对级联Langmuir波在45度非共振等离子体线中的多次散射。(6)研究通过平行传播Langmuir波对频率上移的HFPLs进行直接参数激励并降低混合衰减模式的可能性。

Investigators provide applicable theoretical basis for nonlinear wave-wave couplings in ionospheric HF heating, and apply the theory to experimental observations by Sulzer and Fejer in 1994. They are deriving a set of general coupled mode equations for studying secondary parametric instabilities, including nonlinearities in the derivations. Specifically, they: (1) derive coupled mode equations, (2) compare different cases among nonlinear coupling terms, (3) perform case studies exemplifying the importance of each nonlinearity, and a systemic study of secondary parametric instabilities, (4) determine the spectral distribution of Langmuir waves in a specific frequency range, (5) study multiple scattering of cascading Langmuir waves by parametrically excited ion acoustic waves into forty-five degree off-resonance plasma lines, and (6) investigate possible direct parametric excitation of frequency upshifted HFPLs together with lower hybrid decay mode by parallel propagating Langmuir waves.