Conjugate Photoelectron Energy Spectra Derived From Coincident FUV and Radio Measurements

Abstract
We present a method for estimating incident photoelectrons energy spectra as a function of altitude by combining global scale far-ultraviolet (FUV) and radio-occultation (RO) measurements. This characterization provides timely insights important for accurate interpretation of ionospheric parameters inferred from the recently launched Ionospheric Connection Explorer (ICON) observations. Quantification of photoelectron impact is enabled by the fact that conjugate photoelectrons (CPEs) directly affect FUV airglow emissions but not RO measurements. We demonstrate a technique for estimation of photoelectron fluxes and their spectra by combining coincident ICON and COSMIC2 measurements and show that a significant fraction of ICON-FUV measurements is affected by CPEs during the winter solstice. A comparison of estimated photoelectron fluxes with measured photoelectron spectra is used to gain further insights into the estimation method and reveals consistent values within 10–60 eV.
Year of Publication
2021
Journal
Geophysical Research Letters
Volume
48
Number of Pages
e2021GL095839
ISSN Number
1944-8007
URL
https://onlinelibrary.wiley.com/doi/abs/10.1029/2021GL095839
DOI
10.1029/2021GL095839