NUMERICAL MODELING OF PHOTOELECTRON IMPACT EXCITATION OF OI 8446 A EMISSION

Huang, Yu

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https://hdl.handle.net/2142/97833 Copy

Description

Title

NUMERICAL MODELING OF PHOTOELECTRON IMPACT EXCITATION OF OI 8446 A EMISSION

Author(s)

Huang, Yu

Contributor(s)

Waldrop, Lara

Issue Date

2016

Keyword(s)

• Airglow
• Photoelectron
• Atom Oxygen
• 844.6nm
• Atmosphere Remote Sensing

Abstract

Airglow is a key remote sensing observable that can be used to infer chemical reaction processes and atmospheric state parameters such as atmospheric state parameters such as wind velocity, temperature, density, and composition that would be present in Earth's atmosphere. This project is focused on the study of airglow emissions generated by photoelectron impact on neutral constituents in the terrestrial thermosphere. Photoelectrons are produced by photo-ionization of thermospheric neutrals by solar EUV radiation. When high-energy photoelectrons collide with neutral atoms, they excite the electrons within the neutral atom. These excited electrons return to their ground state by emitting a photon whose wavelength is proportional to the excitation energy. These photon emission wavelengths and intensities are representative of the specific neutral element population and its density at the corresponding thermospheric altitude. In this work our goal is to study the atomic oxygen (O) density in the upper atmosphere by numerically modeling the observations of 844.6 nm oxygen (O) emissions at 250 km to 600 km altitude. There is an existing numerical model with limited capabilities as it can only simulate line-of-sight volume emission rate in the zenith look direction (elevation angle of 90o with respect to ground). Hence, we developed new algorithms to extend the model’s capability to simulate arbitrary line-of-sight orientations and enable oxygen density sensing under a wider variety of observing conditions. We validate our model using existing ground-based data.

Type of Resource

text

Language

en

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http://hdl.handle.net/2142/97833

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