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Abstract Observations from past space missions report on the significant abundance of N+, in addition to those of O+, outflowing from the terrestrial ionosphere and populating the near‐Earth region. However, instruments on board current space missions lack the mass resolution to distinguish between the two, and often the role of N+in regulating the magnetosphere dynamics, is lumped together with that of O+ions. For instance, our understanding regarding the role of electromagnetic ion cyclotron (EMIC) waves in controlling the loss and acceleration of radiation belt electrons and ring current ions has been based on the contribution of He+and O+ions only. We report the first observations by Van Allen Probes of linearly polarized N+EMIC waves, which confirm the presence of N+in the terrestrial magnetosphere, and open up new avenues to particle energization, loss, and transport mechanisms, based on the altered magnetospheric plasma composition.
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Characterization of N + Abundances in the Terrestrial Polar Wind Using the Multiscale Atmosphere‐Geospace Environment
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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- Award ID(s):
- 1936186
- PAR ID:
- 10593332
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Space Physics
- Volume:
- 129
- Issue:
- 5
- ISSN:
- 2169-9380
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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