Bibliography

Quantifying the Impact of Dynamic Storm-Time Exospheric Density on Plasmaspheric Refilling

As soon as the outer plasmasphere gets eroded during geomagnetic storms, the greatly depleted plasmasphere is replenished by cold, dense plasma from the ionosphere. A strong correlation has been revealed between plasmaspheric refilling rates and ambient densities in the topside ionosphere and exosphere, particularly that of atomic hydrogen (H). Although measurements of H airglow emission at plasmaspheric altitudes exhibit storm-time response, temporally static distributions have typically been assumed in the H density in plasmasphere modeling. In this presentation, we evaluate the impact of a realistic distribution of the dynamic H density on the plasmaspheric refilling rate during the geomagnetic storm on March 17, 2013. The temporal and spatial evolution of the plasmaspheric density is calculated by using the Ionosphere-Plasmasphere Electrodynamics (IPE) model, which is driven by a global, 3-D, and time-dependent H density distribution reconstructed from the exospheric remote sensing measurements by NASA’s TWINS and TIMED missions. We quantify the spatial and temporal scales of the refilling rate and its correlation with H densities.

Waldrop, Lara; Cucho-Padin, Gonzalo; site, this; Maruyama, Naomi; site, this;

Published by: Earth and Space Science Open Archive ESSOAr      Published on: jan

YEAR: 2021     DOI: 10.1002/essoar.10505771.1

Atmospheric Sciences; Atmospheric Sciences / Magnetospheric Particles

Understanding the role of exospheric density in the ring current recovery rate

Atomic Hydrogen (H) is the most abundant constituent of the terrestrial exosphere. Its charge exchange interaction with ring current ions (H+ and O+) serves to dissipate magnetospheric energy during geomagnetic storms, resulting in the generation of energetic neutral atoms (ENAs). Determination of ring current ion distributions through modeling depends critically on the specification of the exospheric H density distribution. Furthermore, theoretical studies have demonstrated that ring current recovery rate after the storm onset directly correlates with the H density. Although measurements of H airglow emission at altitudes [3,6] Re exhibit storm-time variations, the H density distributions used in ring current modeling are typically assumed to be temporally static during storms. In this presentation, we will describe the temporal and spatial evolution of ring current ion densities in response to a realistically dynamic exospheric H density distribution using the Comprehensive Inner Magnetosphere-Ionosphere Model (CIMI). The exospheric densities used as input to the model are fully data-driven, derived as global, 3D, and time-dependent tomographic reconstructions of H emission data acquired from Lyman-alpha detectors onboard the NASA TWINS satellites during the geomagnetic storm that occurred on March 17, 2013. We will examine modeled ring current recovery rates using both dynamic and static reconstructions and evaluate the impact of realistic storm-time exospheric variability on the simulations.

Cucho-Padin, Gonzalo; site, this; Ferradas, Cristian; Waldrop, Lara; Fok, Mei-Ching; site, this;

Published by: Earth and Space Science Open Archive ESSOAr      Published on: jan

YEAR: 2021     DOI: 10.1002/essoar.10505770.1

Atmospheric Sciences; Atmospheric Sciences / Magnetospheric Particles

Ultraviolet Observations and a Theory of STEVE

A search for ultraviolet (UV) emissions in satellite data during known STEVE (Strong Thermal Emission Velocity Enhancement) events found that simultaneous subauroral UV arcs (SUA) were usually, but not always present in the Southern Hemisphere despite coverage of the conjugate STEVE location. From 2005 to 2020 a systematic search for SUA found over 100 cases with a mean Magnetic Local Time (MLT) of 316°, standard deviation 13° and hemispheric asymmetry. Frequently coincident continuum UV and visible emissions, upwelling plasma flux, and downward Field Aligned Currents were observed. Occassionally coincident MeV protons were observed. A theory of solar MeV protons and comoving keV electrons following a Parker spiral can explain these phenomena.

Bennett, Charles; site, this;

Published by: Earth and Space Science Open Archive ESSOAr      Published on: apr

YEAR: 2021     DOI: 10.1002/essoar.10504577.6

Atmospheric Sciences; Atmospheric Sciences / Airglow; Atmospheric Sciences / Aurora; Atmospheric Sciences / Ionosphere; Atmospheric Sciences / Magnetospheric Particles; Atmospheric Sciences / Precipitation Physics; Atmospheric Sciences / Solar Wind