III: Generation of Turbulence and Wave-Induced Heating During Ionospheric Modification

PI将采用一种新的数值方法来研究高频加热器产生的朗缪尔波如何受到加热器强度剖面的高度变化的影响，以及在更长的流体动力学时间尺度上，如何受到加热器引起的等离子体密度空间扭曲的影响。为了量化电离层不均匀性对Langmuir波能量的影响，PI将根据观测和理论模型，在数值上确定驱动密度和热强度剖面绝对不稳定性的修正阈值。研究的这两个组成部分将共同回答：(1)加热器能量在电离层中的何处以及如何转换为朗缪尔波（预处理前后）？(2)什么是Langmuir波和电子的自洽动力学非线性演化？(3)在加热区域外观察到的加速电子分布是怎样的？

The PI will employ a new numerical approach for studying how the generation of Langmuir waves by the HF heater is influence by altitude variation in the heater intensity profile, and - on longer hydrodynamical time scales - by heater-induced spatial distortions in the plasma density. In order to quantify the effects ionospheric inhomogeneity has on Langmuir wave energy, the PI will numerically determine modified thresholds for driving absolute instabilities for density and heater-intensity profiles based on observations and theoretical models. Together, these two components of the research will answer: (1) where and how is heater energy conve3rted to Langmuir waves in the ionosphere (before and after preconditioning)? (2) what is the self-consistent kinetic nonlinear evolution of Langmuir waves and electrons? And (3) what is the distribution of accelerated electrons observed outside the heated region?