There is still an inadequate understanding of how the interplanetary magnetic field (IMF) east‐west component (
We present the observational and modeling study focused on the major factors determining the spatiotemporal structure of the high‐latitude ionospheric plasma density enhancement—the tongue of ionization (TOI) structure—during the 2015 St. Patrick's Day geomagnetic storm. We use the Global Self‐consistent Model of the Thermosphere, Ionosphere, Protonosphere (GSM TIP) to reproduce the plasma density distribution, and the results are compared with the observational data as deduced from the ground‐based global positioning system total electron content and in situ plasma probe measurements at different altitudes. Both the simulation and observation results show that a large‐scale TOI‐like structure of enhanced plasma density extends from the dayside midlatitude region toward the central polar cap along the antisunward cross‐polar convection flow. We reveal an important role of the clockwise convection cell rotation for the modification of TOI structure. According to model results during the storm main phase, the neutral thermospheric composition, particularly the “tongue” in n(N2), modifies the spatial structure of TOI in such a way that (1) the near‐pole region of enhanced plasma density is shifted to the duskside and, (2) at
- NSF-PAR ID:
- 10375368
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Space Weather
- Volume:
- 17
- Issue:
- 7
- ISSN:
- 1542-7390
- Page Range / eLocation ID:
- p. 1073-1089
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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