Zhao Hai-Sheng, Feng Jie, Xu Zheng-Wen, Liu Ya-Xin, Xue Kun, Wu Jian, Wang Cheng, Xie Shou-Zhi, Peng Huai-Yun
National Key Laboratory of Electromagnetic Environment, China Research Institute of Radiowave Propagation, Qingdao, 266107, China.
Kunming Electro-Magnetic Environment National Observation and Research Station, China Research Institute of Radiowave Propagation, Qujing, 655500, China.
Sci Rep. 2024 Jun 9;14(1):13234. doi: 10.1038/s41598-024-64011-w.
The ionosphere can be artificially modified by employing ground-based high-power high-frequency electromagnetic waves to irradiate the ionosphere. This modification is achieved through the nonlinear interaction between the electromagnetic waves and the ionospheric plasma, leading to changes in the physical properties and structure of the ionosphere. The degree of artificial modification of the ionosphere is closely related to the heating energy density of high-frequency pump waves. Due to the high density of neutral constituents in the lower ionosphere and the high frequency of electron-neutral collisions, the energy of heating pump waves will be absorbed and attenuated during the penetration of the low ionosphere, seriously affecting the heating effect. This paper proposes a method to reduce the absorption of ionospheric heating pump waves by releasing electron attachment chemicals into low ionosphere to form a large-scale electron density hole. A model for mitigating pump waves absorption based on SF release is established, and the absorption at different frequencies is quantitatively calculated. The propagation characteristics of high-frequency signals in ionospheric holes are studied using a three-dimensional ray tracing method, and the results demonstrate that the chemical release method not only reduces the absorption attenuation of heating pump waves but also forms spherical electron density holes, which exhibit a focusing effect on the heating beam and enhance the heating effect. The results are of great significance for understanding the nonlinear interaction between electromagnetic wave and ionospheric plasma and improving the ionospheric heating efficiency.
通过利用地面大功率高频电磁波照射电离层，可以对电离层进行人工修改。这种修改是通过电磁波与电离层等离子体之间的非线性相互作用实现的，从而导致电离层的物理性质和结构发生变化。电离层的人工修改程度与高频泵浦波的加热能量密度密切相关。由于低电离层中中性成分的密度较高以及电子-中性碰撞的频率较高，加热泵浦波的能量在穿透低电离层时会被吸收和衰减，严重影响加热效果。本文提出了一种通过向低电离层释放电子附着化学物质以形成大规模电子密度空洞来减少电离层加热泵浦波吸收的方法。建立了基于SF释放的减轻泵浦波吸收的模型，并对不同频率下的吸收进行了定量计算。利用三维射线追踪方法研究了高频信号在电离层空洞中的传播特性，结果表明化学释放方法不仅降低了加热泵浦波的吸收衰减，还形成了球形电子密度空洞，这些空洞对加热波束表现出聚焦效应并增强了加热效果。这些结果对于理解电磁波与电离层等离子体之间的非线性相互作用以及提高电离层加热效率具有重要意义。
