Simulating Storm Enhanced Densities (SEDs) Using Ionosphere-Plasmasphere-Electrodynamics (IPE) Model

Abstract:

Storm-enhanced densities (SEDs) are increased ion concentrations seen in longitudinally narrow regions extending from middle latitudes to the polar cusp region. Signatures of SEDs have been observed in total electron content measurements obtained from networks of GPS receivers. They have also been observed as plasmaspheric plumes by the extreme ultraviolet imager onboard IMAGE spacecraft, and more recently by the Van Allen Probes. Various mechanisms have been suggested to explain these density enhancements. In order to assess these theories and advance the understanding of the processes causing the dynamical evolution of SEDs in the ionosphere, a global ionosphere-plasmasphere model with a realistic specification of storm time dependent electric field and neutral atmosphere is required. In this study, the recently developed Ionosphere-Plasmasphere-Electrodynamics (IPE) model is used to simulate the SED observed during the March 17th, 2013 geomagnetic storm event. The IPE model provides time dependent, global, three dimensional plasma densities for nine ion species, electron and ion temperatures, parallel and perpendicular velocities of ionosphere and plasmasphere. The geomagnetic storm high latitude drivers rely on the empirical models of the time-dependent Weimer magnetospheric convection and TIROS/NOAA auroral precipitation patterns. The neutral atmosphere composition and winds come from either empirical the MSIS and HWM models, or the Coupled model of the Thermosphere, Ionosphere, Plasmasphere and electrodynamics (CTIPe). The simulations are used to evaluate the relative importance between electric field, neutral wind and neutral composition in reproducing the SEDs. Furthermore, observations from ground and space are used to validate the model results.