Investigation of a Neutral “Tongue” Observed by GOLD During the Geomagnetic Storm on May 11, 2019

Abstract

The response of thermospheric composition to geomagnetic storms has been investigated for several decades. The first such study was carried out by Seaton (1956), who proposed that an increase of molecular oxygen (O 2 ) number density might account for the decrease of electron density during a major storm that took place on January 25, 194925, . Prölss (198025, , 1981 summarized how geomagnetic storms influence the distribution of neutral species in the thermosphere. They suggested that the composition disturbances were restricted to high latitudes in the later afternoon and evening sectors, and the maximum disturbances occurred near the boundary of the auroral zone. The perturbed neutral composition was also found to expand towards mid-and even low-latitudes in the night and early morning sectors. In the early morning sector, there were seasonal variations in the areas of composition disturbance zone in mid and low latitudes. These initial findings have since been validated by a number of observational and modeling studies (Burns et al.

Variations in Thermosphere Composition and Ionosphere Total Electron Content Under “Geomagnetically Quiet” Conditions at Solar‐Minimum

“…10.1029/2021GL093300 6 of 9 the dominant process in generating the ∑O/N 2 and TEC variations, though it may still be a secondary or more minor process. Diagnostic analysis of the O continuity equation (Burns et al, 1989;Cai et al, 2020Cai et al, , 2021 has been performed to obtain insight into the variations of mid-latitude ∑O/N 2 in both cases. ∑O/N 2 occurs approximately on a constant pressure surface.…”

The Height‐Dependent Delayed Ionospheric Response to Solar EUV

“…TIE‐GCM calculates the major species (O, O 2 , and N 2 ) using vertical molecular diffusion, vertical eddy diffusion, horizontal and vertical advection as well as production and loss due to chemical reactions (Cai et al., 2021; Qian et al., 2014; Sutton et al., 2015; Yu et al., 2021). The O + density is calculated according to the continuity equation considering transport due to neutral winds, transport due to ambipolar diffusion, E × B transport as well as production Q and loss L due to chemical reactions (Liu et al., 2016) $$$\frac{\partial n}{\partial t}-Q+L\cdot n=-\nabla \left(n\cdot {\mathbf{v}}_{i}\right).$$$ The ion velocity v i combines the different transport processes in Equation .…”

Thermospheric Composition and Solar EUV Flux From the Global‐Scale Observations of the Limb and Disk (GOLD) Mission

“…There are a number of recent publications demonstrating the application of GOLD ON2 data. Cai et al (2020) and Cai et al (2021) looked at percentage differences between consecutive days to study the response of ΣO/N 2 to weak geomagnetic activity, both in terms of changes in magnitude as well as spatial morphology.…”