| NSF Org: |
AGS Division of Atmospheric and Geospace Sciences |
| Recipient: |
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| Initial Amendment Date: | July 26, 2022 |
| Latest Amendment Date: | July 26, 2022 |
| Award Number: | 2225363 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Chia-Lin Huang
chihuang@nsf.gov (703)292-7544 AGS Division of Atmospheric and Geospace Sciences GEO Directorate for Geosciences |
| Start Date: | September 1, 2022 |
| End Date: | August 31, 2025 (Estimated) |
| Total Intended Award Amount: | $518,072.00 |
| Total Awarded Amount to Date: | $518,072.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
620 MICHIGAN AVE NE WASHINGTON DC US 20064-0001 (202)635-5000 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
8800 Greenbelt Rd Greenbelt MD US 20771-2400 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | MAGNETOSPHERIC PHYSICS |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
The terrestrial ring current is an electric current flowing around the Earth, thousands of miles above the atmosphere. The ring current is one of the principal current systems that control conditions in the space above the atmosphere where orbiting satellites operate. Abrupt changes of several orders of magnitude in this current may occur, responsible for global decreases in the Earth's surface magnetic field, known as geomagnetic storms. The storm-time ring current is thus associated with harmful space weather effects, which motivates the study of its formation, dynamics, and decay. As the ring current decays on time scales of hours to several days, its energy is released into space and the atmosphere by loss processes, whose contribution to this decay remains one of the outstanding questions related to the ring current. This project aims to study the causes and effects of the storm-time decay of the ring current ions, which are the main carriers in the ring current. The proposed work can significantly advance our knowledge of the dynamics of the Earth's ring current, including its space weather effects and the coupled space environment. Moreover, as part of the proposed activities, high school students will benefit from state-of-the-art science research by participating in the NASA summer internship program at NASA Goddard Space Flight Center.
As the ring current decays on time scales of hours to several days during the storm recovery phase, its energy is released into space, the atmosphere, and the plasmasphere by means of loss processes such as charge exchange, Coulomb collisions, field line curvature scattering, resonant interactions with plasma waves, and drift out loss to the dayside magnetopause. This project addresses unresolved science questions regarding the decay of the ring current. The methodology will consist of numerical simulations and validation with observational data. The primary modeling tool in this investigation will be the Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model. This state-of-the-art kinetic model considers necessary couplings between the ring current and the other plasma populations in the inner magnetosphere. Simulation studies of actual storm events will be performed to quantify how individual processes result in ring current losses and how the associated ion precipitation affects the ionospheric conductance and its feedback to the magnetosphere. The expected result from this modeling work is a systematic quantification of the roles of the different loss mechanisms. Achieving this quantification requires an investigation that models the storm-time ring current, accounting for all the identified loss mechanisms. Furthermore, it is known that the inner magnetosphere responds distinctively to storms produced by different solar wind drivers, i.e., driven by coronal mass ejections (CMEs) or by co-rotating interaction regions (CIRs). The proposed research will thus perform a systematic analysis of the relative roles of the different ion loss processes during storms of CME and CIR drivers and the impacts on the magnetosphere-ionosphere coupled system. Consequently, this study will advance our current knowledge by providing a comprehensive view of the physical processes during, and leading to, the decay of the ring current in different contexts of solar wind driving.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
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