Abstract Penetrating and disturbed electric fields develop during geomagnetic storms and are effective in driving remarkable changes in the nightside low latitude ionosphere over varying time periods. While the former arrive nearly instantaneously with the changes in the solar wind electric field, the latter take more time, requiring auroral heating to modify upper atmospheric winds globally, leading to changes in the thermospheric wind dynamo away from the auroral zones. Such changes always differ from the quiet time state where the winds are usually patterned after daytime solar heating. We use the Multiscale Atmosphere‐Geospace Environment model (MAGE) and observations from the NASA Ionospheric Connection Explorer (ICON) mission to investigate both during the 7–8 July 2022 geomagnetic storm event. The model was able to simulate the penetrating and disturbed electric fields. The simulations showed enhanced westward winds and the wind dynamo induced upward ion drift confirmed by the ICON zonal wind and ion drift observations. The simulated zonal wind variations are slightly later in arrival at the low latitudes. We also see the penetrating electric field opposes or cancels the disturbed electric field in the MAGE simulation.
more »
« less
Penetrating electric field during the Nov 3–4, 2021 geomagnetic storm
We simulated the Nov 3-4, 2021 geomagnetic storm event penetrating electric field using the Multiscale Atmosphere-Geospace Environment (MAGE) model and compared with the NASA ICON observation. The ICON observation showed sudden enhancement of the vertical ion drift when the penetrating electric field arrived at the equatorial region. The MAGE model simulated vertical ion drifts have the similarly fast enhancement that shown in the ICON data at the same UT time and satellite location. Hence, ICON ion drift data was able to verify MAGE simulation, which couples the magnetospheric model was able to simulate the penetrating electric field very well.
more »
« less
- Award ID(s):
- 2120511
- PAR ID:
- 10539417
- Publisher / Repository:
- JASTP
- Date Published:
- Journal Name:
- Journal of Atmospheric and Solar-Terrestrial Physics
- Volume:
- 257
- Issue:
- C
- ISSN:
- 1364-6826
- Page Range / eLocation ID:
- 106219
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Using the latest coupled geospace model Multiscale Atmosphere‐Geospace Environment (MAGE) and observations from Jicamarca Incoherent scatter radar (ISR) and ICON ion velocity meter (IVM) instrument, we examine the pre‐reversal enhancement (PRE) during geomagnetic quiet time period. The MAGE shows comparable PRE to both the Jicamarca ISR and ICON observations. There appears to be a discrepancy between the Jicamarca ISR and ICON IVM with the later showed PRE about two times larger (∼40 m/s). This is the first time that MAGE is used to simulate the PRE. The results show that the MAGE can simulate the PRE well and are mostly consistent with observations.more » « less
-
Regional simulations of equatorial spread F driven with, and an analysis of, WAM-IPE electric fieldsA three-dimensional, regional simulation is used to investigate ionospheric plasma density irregularities associated with Equatorial Spread F. This simulation is first driven with background electric fields derived from ISR observations. Next, the simulation is driven with electric fields taken from the WAM-IPE global model. The discrepancies between the two electric fields, particularly in the evening prereversal enhancement, produce disagreeing simulation results. The WAM-IPE electric fields are then studied through a simple sensitivity analysis of a field-line integrated electrodynamics model similar to the one used in WAM-IPE. This analysis suggests there is no simple tuning of ion composition or neutral winds that accurately reproduce ISR-observed electric fields on a day-to-day basis. Additionally, the persistency of the prereversal enhancement structure over time is studied and compared to measurements from the ICON satellite. These results suggest that WAM-IPE electric fields generally have a shorter and more variable correlation time than those measured by ICON.more » « less
-
Abstract We use the TIEGCM‐NG nudged by MAGIC gravity waves to study the impacts of a severe thunderstorm system, with a hundred tornado touchdowns, on the ionospheric and thermospheric disturbances. The generated waves induce a distinct concentric ring pattern on GNSS TIDs with horizontal scales of 150–400 km and phase speeds of 150–300 m/s, which is well simulated by the model. The waves show substantial vertical evolution in period, initially dominated by 0.5 hr at 200 km, shifting to 0.25 hr and with more higher‐frequency waves appearing at higher altitudes (∼400 km). The TADs reach amplitudes of 100 m/s, 60 m/s, 80 K, and 10% in horizontal winds, vertical wind, temperature, and relative neutral density, respectively. Significantly perturbations in electron density cause dramatic changes in its nighttime structure around 200 km and near the EIA crest. The concentric TIDs are also simulated in ion drifts and mapped from the Tornado region to the conjugate hemisphere likely due to neutral wind‐induced electric field perturbations. The waves manage to impact the ionosphere at altitudes of ICON and COSMIC‐2, which pass through the region of interest on a total of 8 separate orbits. In situ ion density observations from these spacecrafts reveal periodic fluctuations that frequently show good agreement with the TIEGCM‐NG simulation. The O+fraction observations from ICON indicate that the density fluctuations are the result of vertical transport of the ions in this region, which could result from either direct forcing by neutral winds or electrodynamic coupling.more » « less
-
Abstract Results from a dynamo electric field model are presented to examine the consistency of the widely used empirical models of low‐latitude plasma drifts and thermospheric neutral winds. The sector defined by the Jicamarca Radar measured plasma drifts is used due to the greater certainty of the empirical vertical plasma drifts. The plasma drifts produced by the Horizontal Wind Model (HWM) in a coupled ionosphere‐electric field model for geomagnetically quiet and moderate solar conditions are compared against empirical models of equatorial plasma drifts for the Peruvian sector. The HWM generates reasonable sunset prereversal enhancement of the vertical drift in all but May, June, July, and August when no prereversal enhancement exists in the empirical results. The daytime vertical drifts are deficient during all seasons. A solar diurnal and semi‐diurnal tidal forcing are required in the E region (100–150 km) to bring the HWM into better agreement as a dynamo driver for the daytime electric fields associated with the broad Solar Quiet current system.more » « less
An official website of the United States government

