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Measurements of O+ composition in the F-region from a Langmuir Probe aboard the International Space Station

Shantanab
Debchoudhury
EMBRY-RIDDLE AERONAUTICAL UNIVERSITY
Abstract text

The Floating Potential Measurement Unit (FPMU) on board the International Space Station (ISS) includes a spherical wide-sweeping Langmuir Probe (WLP) that has been operated intermittently for over 14 years. With over 80% of these observations spanning the most recent solar cycle 24 from 2011 to 2019, FPMU has been in a unique position to monitor the variability of the F-region ionosphere at ~400 km altitude. Traditional Langmuir Probe estimates include electron density and temperature. However, we have extracted ion composition information from the ion saturation region of the Langmuir probe, assuming O+ and H+ to be the only constituents. The in-situ plasma measurements reveal striking findings such as deep O+ dropouts in the post-midnight sector during solar minimum, which are often much severe compared to IRI predictions. The O+ abundance can drop to less than 80% of background total quasi-neutral plasma density for many orbits for pre-dawn local times. In recent years, with the launch of the ICON and COSMIC-2 missions, it is possible to obtain a multi-layer observation based understanding of the topside ionosphere during these depletions, instances of which are presented in the poster.

Authors
Shantanab Debchoudhury
Aroh Barjatya
Joseph I. Minow
Victoria N. Coffey
Linda N. Parker
Non-Student
Poster category
IRRI - Irregularities of Ionosphere or Atmosphere