Storm Enhanced Densities simulations using the Ionosphere Plasmasphere Electrodynamics (IPE) Model

Abstract:

Storm time response of the middle latitude ionosphere goes through different phases of positive and negative storms for different events. Storm Enhanced Densities (SEDs) are particularly difficult to self-consistently categorize with physical models. The area of enhanced density is surrounded by steep density gradients and appears to progress rapidly through mid-latitudes and into the polar regions. The goal of this study is to improve our scientific understanding of the plasma height variations associated with SEDs, specifically to determine the relative role of the various drivers including neutral wind, composition, and electric fields.

A new Ionosphere-Plasmasphere-Electrodynamics (IPE) model used in this study has been developed by collaboration between CU CIRES, NOAA/SWPC, NOAA/GSD and NCAR/HAO. The main objectives are to improve our specification of ionosphere and plasmasphere in response to external forcing from both above and below, and to couple to whole atmosphere models for understanding the interaction between the terrestrial weather to space weather. The model describes the time dependent, three-dimensional, global density of nine ion species, electron density, temperatures of electron and ions in the ionosphere and plasmasphere. The parallel plasma transport is based on the Field Line Interhemispheric Plasma (FLIP) Model [Richards et al., 1990]. A realistic model of Earth’s magnetic field is implemented by using the APEX coordinate system [Richmond, 1995]. Global, seamless plasma transport perpendicular to the magnetic field has been included all the way from the equator to the poles. The electrodynamics solver based on the TIEGCM [Richmond and Maute, 2014] calculates the global electric field self-consistently.

This presentation focuses on an impact of IGRF on the variations of plasma gradients associated with SEDs. In particular, difference between IGRF and dipole coordinate system is quantified. Furthermore, the relative roles of the various storm time drivers including wind, composition and electric field is examined.