Motivation: the accumulation, transport, and energization of the o+ ions in the plasma sheet and the inner magnetosphere is a compelling issue of magnetospheric physics: i) the o+ ions are an…

This is a $744,398.43 grant awarded by the National Aeronautics and Space Administration (NASA) to The Johns Hopkins University to investigate the accumulation, transport, and energization of oxygen ions (O+) in the plasma sheet and inner magnetosphere. The research aims to address key science questions on how O+ ion properties evolve during geomagnetic storms, how the spatial distribution of O+ ions depends on solar wind conditions and geomagnetic indices, and where the transport of O+ ions transitions from non-adiabatic to adiabatic. The study will leverage data from instruments on the Geotail, Van Allen Probes, and other spacecraft, as well as global magnetohydrodynamic and test-particle simulations. This grant directly supports the Heliophysics Decadal Survey goal of determining the dynamics and coupling of Earth's magnetosphere, ionosphere, and atmosphere. The award does not have a set-aside designation and runs through January 17, 2024.

Motivation: the accumulation, transport, and energization of the o+ ions in the plasma sheet and the inner magnetosphere is a compelling issue of magnetospheric physics: i) the o+ ions are an important constituent of the ring current population, especially during intense geomagnetic storms as their energy density can become comparable to that of the h+ ions, II) the presence of o+ ions at least partially controls the overall magnetotail dynamics and solar wind-magnetosphere coupling by significantly affecting the reconnection rates. Despite the important role of o+ ions in magnetospheric dynamics, just how they populate the plasma sheet and inner magnetosphere, and how the o+ ION distribution depends on external (solar wind) and internal (geomagnetic indices) conditions remain compelling open questions. Science goals and objectives: in the present project we seek to investigate, through synergy between data analysis and state-of-theart numerical simulations, the spatial and temporal evolution of the o+ ION properties (e.g. temperature, number density, and energy density) throughout the magnetosphere, from the plasma sheet to within geosynchronous orbit. More specifically we will addresses the following three science questions: SQ1. Response time during geomagnetic storms: how do o+ ION properties (average energy, number density, and energy density) evolve during the course of geomagnetic storms both in the plasma sheet and inner magnetosphere? Following the sudden commencement of a geomagnetic storm, how do the response times of those o+ ION properties depend on radial distance from the earth? SQ2. Dependence on internal and external conditions: how does the spatial distribution of o+ ions depend on solar wind conditions (external)? How does the spatial distribution of o+ ions depend on geomagnetic indices (internal)? SQ3. Transport from the tail to within geosynchronous orbit: in which region does the transport of o+ ions transition from nonadiabatic to adiabatic? Methodology: for the observational part of our project we will use geotail epic/stics instrument data to investigate o+ properties in the plasma sheet, and data from the hope and rbspice instruments on board van allen probes to investigate o+ properties in the inner magnetosphere. For the modeling part of our project we will use i) multi-fluid LFM (mflfm) global MHD code that includes o+ ions as a fluid to investigate o+ ionospheric outflow and subsequent transport within the magnetosphere, II) 3D testparticle simulations in LFM-RCM simulated electric and magnetic fields to investigate non-adiabatic o+ transport from the plasma sheet into the inner magnetosphere. The combined data-model approach of this project will allow US to comprehensively address o+ dynamics in the coupled magnetosphere ionosphere (m-i) system. Revelance: the proposed investigation will provide new insights on o+ ION dynamics in the coupled m-i system, therefore, IT directly addresses high-level science goal #2 from the heliophysics decadal survey, namely: determine the dynamics and coupling of earth s magnetosphere, ionosphere, and atmosphere and their response to solar and terrestrial inputs .