不同初始扰动对电离层扩展F影响的数值模拟

重力波、中性风场、电场是激发电离层扩展F的主要影响因子,本文基于中低纬电离层扩展F发展的物理模型,通过电场强度、背景风场对扩展F影响作用的分析和经验对比,首先验证了模型的有效性,后借助该模型数值模拟了给定背景环境下三种尺度初始电子密度扰动条件下扩展F的发展情况,同时研究了利用化学物质释放实现一定尺度扰动,进而激发扩展F的过程.结果表明,较强的背景电场、东向风场有利于扩展F的形成和抬升,与经验结论相吻合;电离层从被作用初始扰动到激发扩展F的过程中存在拐点效应,拐点之后扩展F被激发形成并且抬升迅速,同时短波长扰动相对于长波长扰动更有利于扩展F的激发和发展;化学物质H_2O释放通过耗散电子密度,形成了一定尺度扰动并诱发了扩展F的形成,该方法可作为一种人工激发扩展F的探索手段.

Numerical simulation about the influence of different initial disturbance on the ionosphere spread-F

The triggering role of different factors like gravity wave, neutral wind, and electric field in the formation of ionosphere spread-F is a hot issue. Based on a physical model which is developed to present the development of ionosphere spread-F, the reliability of this model is firstly proved by analysis of the effects of eastward electric field and background wind field on spread-F and comparison with experience. Then, on a given background,the spread-F triggered by three disturbances of the initial electron density of different scale is simulated in this paper. The possibility of causing a certain scale perturbation and triggering spread-F by chemical release is also demonstrated. The results show that strong electric-field intensity and eastward neutral wind are beneficial to the development of spread-F, proving that the physical model is reliable; there is an inflection point of the uplift rate of spread-F in the development process, after which spread-F is triggered and developed, and the electron density disturbances with short wavelength are much more beneficial to the triggering and development of spread-F than that of long wavelength; chemical H₂O can produce localized electron density depletion effectively, and it can form a certain scale initial disturbance of electron density for triggering spread-F in the ionosphere, indicating that chemical release could be used as a way to trigger spread-F artificially.