Improving Predictions of the 3D Dynamic Model of the Plasmasphere

Abstract

In this perspective paper, we review and discuss different ways that can be used to improve the predictions of the models of the plasmaspheric region. The density of the background cold plasma and the plasmapause position are very important to determine the formation and propagation of waves and interactions with the other regions of the magnetosphere. Improvement of predictions includes refinement of the forecast of the geomagnetic indices that influence the density and the temperature of the particles in some models. Progress is also necessary for the understanding of the physical processes that affect the position of the plasmapause and its thickness since this boundary is not always very sharp, especially during low geomagnetic activity. These processes include the refilling after geomagnetic storms and substorms, the links with the ionosphere, and the expanding plasmaspheric wind during prolonged quiet periods. Using observations from in situ satellites like Van Allen Probes (EMFISIS and HOPE instruments), empirical relations can be determined to improve the dependence of the density and the temperature as a function of the radial distance, the latitude, and the magnetic local time, inside and outside the plasmasphere. This will be the first step for the improvement of our 3D dynamic SWIFF plasmaspheric model (SPM).

Correlations Between Giant Undulations and Plasmapause Configurations

“…Figure 4e shows the positive correlations between the L GU and the L PP , indicating that the magnetospheric source region of GUs is typically aligned with the PP surface during geomagnetic storms. The general correspondence between the inner edge of the night-side plasma sheet and the PP has already been well documented in the literature (e.g., Horwitz et al, 1982;Korth et al, 1999;Pierrard et al, 2021). Here we provide further statistical evidence that there is also such a correspondence for the subset of time for which GUs are observed during geomagnetic storms.…”

Assessment of the Earth’s Cold Plasmatrough Modeling by Using Van Allen Probes/EMFISIS and Arase/PWE Electron Density Data

“…This point has been recently discussed in Pierrard, Botek, et al. (2021) as one of the foreseen improvements to the SPM. The Arase/PWE (Plasma Wave Experiment) plasma dedicated instrument (Kasahara et al., 2018) is used here for further verifications of the new parametrization.…”

“…Refilling can be also taken into account in the simulations of the SPM model when analyzing specific cases (Pierrard & Stegen, 2008), but it has not yet been included in an automatic way and is thus not included in Figures 1 and 2 (see Section 6 of the present article for more details). In the present long‐term SPM simulations, the plasmasphere is thus always sharply separated from the plasmatrough by a simple plasmapause boundary, without taking into account the thickness of this layer, the refilling time or the plasmaspheric wind (Pierrard, Botek, et al., 2021), which could dramatically change the density evaluated at the plasmatrough. That is why Figure 2 does not show any transition region between the plasmasphere and the plasmatrough for the SPM values (in green).…”

Statistics and Empirical Models of the Plasmasphere Boundaries From the Van Allen Probes for Radiation Belt Physics

“…Tu et al, 2013;Wang & Shprits, 2019). Physics-based models also provide plasma density and plasmapause location (e.g., Pierrard, Botek, and Darrouzet (2021)), with some models integrating Van Allen Probes measurements (e.g., Botek et al, 2021). Goldstein et al (2019) generated a plasmapause statistical model from the simulations of 60 storms, which this study can help validate.…”

“…The Carpenter and Anderson (1992) plasmapause model (noted CA92) has been largely used for radiation belt studies over the last 10 years (e.g., Cervantes, Shprits, Aseev, & Allison, 2020; Cervantes, Shprits, Aseev, Drozdov, et al., 2020; Glauert et al., 2014; Kim et al., 2011; Malaspina et al., 2020; Ripoll et al., 2016; Saikin et al., 2021; Shprits et al., 2013; Subbotin & Shprits, 2009; W. Tu et al., 2013; Wang & Shprits, 2019). Physics‐based models also provide plasma density and plasmapause location (e.g., Pierrard, Botek, and Darrouzet (2021)), with some models integrating Van Allen Probes measurements (e.g., Botek et al., 2021). Goldstein et al.…”