A Framework for Efficient Calculation of Photoionization and Photodetachment Rates With Application to the Lower Ionosphere

Reza Janalizadeh, Victor P. Pasko

Research output: Contribution to journalArticlepeer-review

Abstract

A framework is developed to model photoionization of metals deposited in the lower ionosphere as a result of meteoric ablation and photodetachment of electrons from negative ions of the Earth's ionosphere due to sources of emission other than solar radiation. A wide range of the electromagnetic spectrum including cases of negligible, moderate, and significant absorption of radiation is considered. We limit our scope to the radiation transport through lower ionospheric regions, in case when molecular oxygen, O2, is considered as the main absorber of radiation as photoabsorption due to ozone is only effective at stratospheric altitudes and molecular nitrogen, N2, is transparent to radiation with wavelengths longer than ∼100 nm. We model photon transport in an exponential atmosphere and derive efficient differential representations of the problem in case of negligible photoabsorption and constant pressure approximations. Photoabsorption asymmetry in the atmosphere is demonstrated in case of photons with absorption scales comparable to the scale height of the atmosphere. The application of the model to photoionization in the lower ionosphere is demonstrated by considering photoionization of meteoric species due to photons of the Lyman-Birge-Hopfield (LBH) band system of N2 observed in the aurora and in the lightning-induced transient luminous events. Furthermore, we model detachment of electrons from negative ions of the ionosphere due to the first positive and the second positive band systems of N2, and the first negative band system of N+2, also observed in the sources mentioned above.

Original languageEnglish (US)
Article numbere2020JA027979
JournalJournal of Geophysical Research: Space Physics
Volume125
Issue number7
DOIs
StatePublished - Jul 1 2020

All Science Journal Classification (ASJC) codes

  • Space and Planetary Science
  • Geophysics

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