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Abstract The High‐latitude Ionosphere Dynamics for Research Applications (HIDRA) model is part of the Multiscale Atmosphere‐Geospace Environment model under development by the Center for Geospace Storms NASA DRIVE Science Center. This study employs HIDRA to simulate upflows of H+, He+, O+, and N+ions, with a particular focus on the relative N+concentrations, production and loss mechanisms, and thermal upflow drivers as functions of season, solar activity, and magnetospheric convection. The simulation results demonstrate that N+densities typically exceed He+densities, N+densities are typically ∼10% O+densities, and N+concentrations at quiet‐time are approximately 50%–100% of N+concentrations during storm‐time. Furthermore, the N+and O+upflow fluxes show similar trends with variations in magnetospheric driving. The inclusion of ion‐neutral chemical reactions involving metastable atoms is shown to have significant effects on N+production rates. With this metastable chemistry included, the simulated ion density profiles compare favorably with satellite measurements from Atmosphere Explorer C and Orbiting Geophysical Observatory 6.
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The Contribution of N + Ions to Earth's Polar Wind
Abstract The escape of heavy ions from the Earth atmosphere is a consequence of energization and transport mechanisms, including photoionization, electron precipitation, ion‐electron‐neutral chemistry, and collisions. Numerous studies considered the outflow of O+ions only, but ignored the observational record of outflowing N+. In spite of 12% mass difference, N+and O+ions have different ionization potentials, ionospheric chemistry, and scale heights. We expanded the Polar Wind Outflow Model (PWOM) to include N+and key molecular ions in the polar wind. We refer to this model expansion as the Seven Ion Polar Wind Outflow Model (7iPWOM), which involves expanded schemes for suprathermal electron production and ion‐electron‐neutral chemistry and collisions. Numerical experiments, designed to probe the influence of season, as well as that of solar conditions, suggest that N+is a significant ion species in the polar ionosphere and its presence largely improves the polar wind solution, as compared to observations.
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- Award ID(s):
- 1664078
- PAR ID:
- 10374829
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 47
- Issue:
- 18
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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