Cross Section Measurements for Excitation and Ionization of Atmospheric Species

这一持续项目将在约翰·霍普金斯大学对大气物种的电子碰撞激发和电离截面进行实验室调查。电离和激发都是由太阳在大气成分上的极紫外线光子通量产生的光电子和极光区中加速的电子产生的。激发和电离也是热层电子向周围大气损失能量的主要过程。因此，我们必须熟悉这些电子碰撞过程的截面，以了解电子能量损失的速率以及它们产生的光发射的强度。具体地说，我们计划测量原子氧离子产生的电离-激发分支比，在离子的所有最终电子态。这项工作应该会大大推进热层模拟和行星大气中的许多感兴趣的过程。

This continuing project will conduct laboratory investigations of electron impact excitation and ionization cross sections for atmospheric species at Johns Hopkins University. Ionization and excitation are produced by both photoelectrons produced by the sun's extreme ultraviolet photon flux on atmospheric constituents and precipitated accelerated electrons in auroral zones. Excitation and ionization are also the main processes by which thermospheric electrons lose energy to the ambient atmosphere. Thus, we must gain familiarity with the cross sections for these electron impact processes to understand the rate of electron energy loss as well as intensities of optical emissions they produce. Specifically, we plan to measure ionization-excitation branching ratios for atomic oxygen ion production in all final electronic states of the ion. The work should significantly advance thermospheric modeling and many processes of interest in planetary atmospheres.