Conjugate Photoelectron Energy Spectra Derived From Coincident FUV and Radio Measurements

Urco, Juan Miguel; Kamalabadi, F.; Kamaci, Ulas; Harding, Brian J.; Frey, H. U.; Mende, S. B.; Huba, J. D.; England, S.; Immel, T. J.

doi:10.1029/2021gl095839

Cited by 6 publications

(5 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At high altitudes (above ∼300 km), where the mean free path of photoelectrons is greater than the atmospheric scale height, photoelectrons can escape from the local ionosphere and travel to the opposite hemisphere along geomagnetic field lines (Hanson, 1963; Nagy & Banks, 1970; Richards & Peterson, 2008; Schunk & Nagy, 1978; Urco et al., 2021). The photoelectrons from the sunlit conjugate hemisphere result in ionization and heating of the neutrals and electrons in the dark hemisphere.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Detection of Signatures of Conjugate Photoelectrons in the Ionosphere and Thermosphere

2022

View full text Add to dashboard Cite

We investigate the impact of conjugate photoelectrons (CPEs) on the topside (∼600 km altitude) ionosphere at low and midlatitudes using measurements of the ion temperature, density, and composition from the first Republic of China satellite during a period of the high to moderate solar activity (March 1999 to June 2004). Elevated ion temperatures and densities are observed in the dark Northern American‐Atlantic sector during the December solstice and in the Australian sector during the June solstice. The oxygen ion fraction and density are also elevated at these locations. These observations indicate that photoelectrons from the conjugate hemisphere heat the local ionospheric plasma. The morphology of the ion temperature in the winter hemisphere is well represented by the solar zenith angle in the sunlit conjugate hemisphere. The CPE hypothesis for the observed ionospheric heating is confirmed by coincident nighttime enhancements of the far ultraviolet airglow measured by the Global Ultraviolet Imager onboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics satellite.

show abstract

Section: Introductionmentioning

confidence: 99%

Simultaneous Detection of Signatures of Conjugate Photoelectrons in the Ionosphere and Thermosphere

2022

View full text Add to dashboard Cite

show abstract

“…By combining global scale far-UV measurements by ICON and radio-occultation measurements from COSMIC2 a method was developed to estimate the incident photoelectron’s energy spectra as a function of altitude (Urco et al. 2021 ). Quantification of photoelectron impact is enabled by the fact that CPEs directly affect FUV airglow emissions but not radio occultation measurements.…”

Section: Science Resultsmentioning

confidence: 99%

In Flight Performance of the Far Ultraviolet Instrument (FUV) on ICON

et al. 2023

Self Cite

View full text Add to dashboard Cite

The NASA Ionospheric Connection Explorer (ICON) was launched in October 2019 and has been observing the upper atmosphere and ionosphere to understand the sources of their strong variability, to understand the energy and momentum transfer, and to determine how the solar wind and magnetospheric effects modify the internally-driven atmosphere-space system. The Far Ultraviolet Instrument (FUV) supports these goals by observing the ultraviolet airglow in day and night, determining the atmospheric and ionospheric composition and density distribution. Based on the combination of ground calibration and flight data, this paper describes how major instrument parameters have been verified or refined since launch, how science data are collected, and how the instrument has performed over the first 3 years of the science mission. It also provides a brief summary of science results obtained so far.

show abstract

“… 2012 ), while a latter study (Urco et al. 2021 ) identified an up to 20-30% 135.6-nm radiance contribution to nighttime recombination emissions, enabling the identification and removal of these emissions, which are surprisingly abundant in nighttime observations, prior to retrieval of O + density profiles. This latter FUV study included GOLD observations as well, finding an initial offset bias multiplier of 0.5 between simultaneous GOLD and ICON measurements, with the ICON intensities being lower than GOLD.…”

Section: Scientific Findingsmentioning

confidence: 99%

“… 2021 ), where a second paper investigated the FUV emission-producing effects of early morning photoelectron fluxes flowing downward along magnetic field lines from magnetically-conjugate sunlit regions (Urco et al. 2021 ). This study suggested a list of corrections to the photoelectron component of the SAMI2-PE ionospheric model (Varney et al.…”

Section: Scientific Findingsmentioning

confidence: 99%

“…The first paper focused on the variations in ion and electron temperatures measured by IVM near sunrise in coordination with the Jicamarca incoherent scatter radar (Derghazarian et al 2021), where a second paper investigated the FUV emission-producing effects of early morning photoelectron fluxes flowing downward along magnetic field lines from magnetically-conjugate sunlit regions (Urco et al 2021). This study suggested a list of corrections to the photoelectron component of the SAMI2-PE ionospheric model (Varney et al 2012), while a latter study (Urco et al 2021) identified an up to 20-30% 135.6-nm radiance contribution to nighttime recombination emissions, enabling the identification and removal of these emissions, which are surprisingly abundant in nighttime observations, prior to retrieval of O + density profiles. This latter FUV study included GOLD observations as well, finding an initial offset bias multiplier of 0.5 between simultaneous GOLD and ICON measurements, with the ICON intensities being lower than GOLD.…”

Section: New Science Investigationsmentioning

confidence: 99%

See 1 more Smart Citation

The Ionospheric Connection Explorer - Prime Mission Review

et al. 2023

View full text Add to dashboard Cite

The two-year prime mission of the NASA Ionospheric Connection Explorer (ICON) is complete. The baseline operational and scientific objectives have been met and exceeded, as detailed in this report. In October of 2019, ICON was launched into an orbit that provides its instruments the capability to deliver near-continuous measurements of the densest plasma in Earth’s space environment. Through collection of a key set of in-situ and remote sensing measurements that are, by virtue of a detailed mission design, uniquely synergistic, ICON enables completely new investigations of the mechanisms that control the behavior of the ionosphere-thermosphere system under both geomagnetically quiet and active conditions. In a two-year period that included a deep solar minimum, ICON has elucidated a number of remarkable effects in the ionosphere attributable to energetic inputs from the lower and middle atmosphere, and shown how these are transmitted from the edge of space to the peak of plasma density above. The observatory operated in a period of low activity for 2 years and then for a year with increasing solar activity, observing the changing balance of the impacts of lower and upper atmospheric drivers on the ionosphere.

show abstract

Conjugate Photoelectron Energy Spectra Derived From Coincident FUV and Radio Measurements

Cited by 6 publications

References 65 publications

Simultaneous Detection of Signatures of Conjugate Photoelectrons in the Ionosphere and Thermosphere

Simultaneous Detection of Signatures of Conjugate Photoelectrons in the Ionosphere and Thermosphere

In Flight Performance of the Far Ultraviolet Instrument (FUV) on ICON

The Ionospheric Connection Explorer - Prime Mission Review

Contact Info

Product

Resources

About