
NSF Org: |
AGS Division of Atmospheric and Geospace Sciences |
Recipient: |
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Initial Amendment Date: | August 23, 2010 |
Latest Amendment Date: | August 9, 2012 |
Award Number: | 1003876 |
Award Instrument: | Continuing Grant |
Program Manager: |
Therese Moretto Jorgensen
AGS Division of Atmospheric and Geospace Sciences GEO Directorate for Geosciences |
Start Date: | September 1, 2010 |
End Date: | August 31, 2013 (Estimated) |
Total Intended Award Amount: | $163,336.00 |
Total Awarded Amount to Date: | $163,336.00 |
Funds Obligated to Date: |
FY 2011 = $53,388.00 FY 2012 = $55,336.00 |
History of Investigator: |
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Recipient Sponsored Research Office: |
10889 WILSHIRE BLVD STE 700 LOS ANGELES CA US 90024-4200 (310)794-0102 |
Sponsor Congressional District: |
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Primary Place of Performance: |
10889 WILSHIRE BLVD STE 700 LOS ANGELES CA US 90024-4200 |
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: |
01001112DB NSF RESEARCH & RELATED ACTIVIT 01001213DB NSF RESEARCH & RELATED ACTIVIT |
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
This project will investigate the transport of plasma from the solar wind into and through Earth's magnetosphere during intervals when the interplanetary magnetic field (IMF) has a northward orientation. During periods of northward IMF the plasma within Earth's plasma sheet often is characterized by having two components, one hot and one relatively cold. The cold component has a somewhat higher temperature on the dawn flank of the magnetosphere than on the dusk side and this suggests that the mechanism by which plasma enters the magnetosphere is not symmetric. This project will use kinetic plasma simulations with the PLAsma Transport Numerical Magnetosphere Model (PLATNUMM) to investigate the plasma entry and transport mechanism. The plasma simulations will be done using realistic magnetic and electric field models for northward IMF conditions. The project will characterize the plasma phase space densities that develop in the layer connecting the magnetosphere with the magnetosheath. The results of the simulation will be compared with observations of the plasma from spacecraft. In addition, the project will simulate the plasma circulation within the plasma sheet in order to understand the asymmetries observed in the large-scale features.
Although periods of northward IMF are typically not periods of strong magnetic activity it is important to understand the evolution of the magnetically quiet times because they form the initial conditions that determine the dynamics of the magnetosphere during magnetically disturbed times. Understanding the transition from magnetically quiet to disturbed times is important for our understanding of space weather phenomena that can impact humans and human engineered systems. Much of the research will be carried out by a female graduate student and the project involves a collaboration between a university research program at UCLA and an independent research and development center (Aerospace Corporation).
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
This project investigated how plasma (ionized gas) from the Sun enters and is transported within the region of space permeated by the Earth’s magnetic field, called the magnetosphere, and why asymmetries exist in the distribution of plasma in this region. There is significant uncertainty about the processes that allow plasma to enter the magnetosphere, and how that plasma flows through the magnetosphere. These processes are important for understanding how the magnetic field changes with time, how plasma is accelerated to high energies, the conditions that control the location and intensity of aurora observed at high latitudes, and the impact of space weather on satellites and astronauts.
We concluded, based on computer simulations of plasma dynamics in the magnetosphere, that part of the asymmetry observed in the distribution of plasma in the magnetosphere is likely due to asymmetric transport of protons due to the Earthward gradient of the Earth’s magnetic field, so-called “gradient drift.” We also investigated a previously observed cooling of plasma in the magnetosphere during “quiet” intervals in which the transport is relatively slow, which we believe may be related to the processes that produce asymmetries. The asymmetric transport is able to explain that cooling on one side of the magnetosphere, but apparently not on the other. This suggests either that other processes are involved in the cooling, or that asymmetric entry of plasma may also be complicating the overall picture of how the magnetosphere is evolving. We furthermore investigated how different temperatures and densities of plasma will affect the evolution of the magnetosphere when strong activity occurs (“magnetic storms”). We found that several processes combine to achieve a strong negative feedback that can mitigate the extent to which the Earth’s magnetic field is deformed during magnetic storms. The primary negative feedback processes include electric shielding and magnetic field stretching, both of which increase as the plasma density in the magnetosphere increases, and these processes mitigate the overall deformation of the Earth’s magnetic field. We quantified how different levels of plasma density and temperature change the negative feedback, and the resulting intensity of the deformation of the Earth’s magnetic field.
This project provided the opportunity to support the education and training of a female graduate student from an underrepresented ethnicity group. As a collaborative project, it has allowed her to obtain a diverse perspective on the objective of space research, having access to the application-focused research environment of a Federally Funded Research and Development Center (The Aerospace Corporation) and the education-focused research environment of a university (UCLA). The student also contributed back to the research community and education of other students by presenting tutorials to other students as part of the NSF Geospace Environment Modeling Summer Workshop. The Aerospace Corporation has an ongoing interest in translating the results and knowledge gained from its research activities into technological capabilities for mitigating the hazards of the space environment on space-borne assets, which benefits society by reducing the total cost of space technology. The results of this research has been presented in peer-reviewed journals and at scientific meetings, such as the NSF Geospace Environment Modeling Workshop.
Last Modified: 09/06/2013
Modified by: Lawrence R Lyons
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