A Theoretical Framework for Photoionization and Photodetachment Rate Calculations in the Lower Ionosphere

该奖项将支持开发由大气烧蚀事件产生的金属物质的光电离和光剥离率的建模框架。光源是多个EUV、UV和O2和N2分子带发射的可见系统，可能是由瞬态发光事件（精灵、精灵、闪电）、极光活动和流星痕迹产生的。这些结果将使具体计算d区和较低热层零星层对电离层组成或电离层动力学可能产生的局部影响成为可能，这些影响具有几公里范围的空间尺度。这项工作将支持一名研究生和一名暑期本科生。这项工作主要是基于这样一个事实，即金属物质的光电离阈值相对于其他大气成分（如N2或O2）的电离阈值相当低。因此，TLE、极光和流星轨迹的照明源将具有足够的能量，以实现中性金属物质的电离，或使电子脱离存在于受流星或沉淀电子或TLE活动影响的区域内的任何电离层负离子。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award will support the development of a modeling framework for photoionization and photo-detachment rates of metallic species generated by meteoric ablation events. The sources are multiple EUV, UV, and visible systems of O2 and N2 molecular band emissions that might be generated by transient luminous events (sprites, elves, lightning), auroral activity, and meteor trails. These results would make possible specific calculations for the D-region and lower thermosphere sporadic layers of possible localized effects upon ionospheric composition or ionospheric dynamics featuring spatial scales a few kms in extent. A graduate student and summer undergraduate students would be supported in this work.This work is based primarily upon the fact that the photo-ionization thresholds of metallic species is quite low relative to the ionization thresholds of other atmospheric constituents such as N2 or O2. Thus, the illumination sources of TLE, aurora, and meteor trails would be sufficiently energetic to achieve the ionization of neutral metallic species or the detachment of electrons from any ionospheric negative ions present within the region affected by meteors or precipitating electrons or TLE activity.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.