
NSF Org: |
AGS Division of Atmospheric and Geospace Sciences |
Recipient: |
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Initial Amendment Date: | March 25, 2014 |
Latest Amendment Date: | March 22, 2016 |
Award Number: | 1261659 |
Award Instrument: | Continuing Grant |
Program Manager: |
Carrie E. Black
cblack@nsf.gov (703)292-2426 AGS Division of Atmospheric and Geospace Sciences GEO Directorate for Geosciences |
Start Date: | April 1, 2014 |
End Date: | March 31, 2019 (Estimated) |
Total Intended Award Amount: | $750,000.00 |
Total Awarded Amount to Date: | $750,000.00 |
Funds Obligated to Date: |
FY 2015 = $250,000.00 FY 2016 = $250,000.00 |
History of Investigator: |
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Recipient Sponsored Research Office: |
4765 WALNUT ST STE B BOULDER CO US 80301-2575 (720)974-5888 |
Sponsor Congressional District: |
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Primary Place of Performance: |
4750 Walnut Boulder CO US 80301-2532 |
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): | SOLAR-TERRESTRIAL |
Primary Program Source: |
01001516DB NSF RESEARCH & RELATED ACTIVIT 01001617DB 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
Over five decades the large scale properties of the solar wind have been described. These observations have shown that the solar wind flow is turbulent. This research project will refine the description of the solar wind by separating the ordered and disordered structures in the solar wind. The proposal posits that hypothesis that space weather is strongly influenced by the cumulative effects of many small disturbances. The researchers are interested in learning if the properties of the turbulent flows in the solar wind are biased by the presence of small scale "fossil" structures whose source is the Sun. The team has proposed to develop and use a series of analysis techniques not currently used in space physics.
This research will support graduate students including training them to use the new techniques. The characterization of the solar wind will be useful for others in studying space weather at Earth.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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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 NSF Solar-Terrestrial project was to look at alternate forms of data analysis to examine the properties of the structure of the solar wind at Earth and the origins of that structure. The solar wind is a supersonic plasma (ionized gas) blowing out from the Sun and filling the solar system. Using spacecraft measurements to examine that plasma wind, it is found that the plasma and the magnetic field it carries are both highly structured (i.e. not smooth or homogeneous). Learning about the properties and origin of this structure is important for at least two reasons: (1) the structure affects the Earth (for example the Earth’s aurora turn on and off as the solar-wind structures pass the Earth) and (2) the structure may carry scientific clues about processes acting at the solar surface (a region where spacecraft measurements can’t be made).
The standard picture of solar wind structure is that it is a manifestation of active flow turbulence in the wind, with the turbulence pulling the solar-wind magnetic-field lines into large eddy structures. An alternate picture of the solar wind turbulence is that it is created at the Sun and carried out with the wind without undergoing much evolution.
The turbulence picture is supported by solar wind data analysis that examines the Fourier frequency spectra of fluctuations in the solar wind. This NSF grant supported an alternative data analysis that looked at the time series of solar wind measurements without making Fourier spectra.
This NSF project was successful at finding further evidence that the structures in the solar wind at Earth are consistent with structure at the Sun. The project also provided some insights (1) about the nature of the Fourier frequency spectra and the causes of one of its major features and (2) about the origin of dominant wave perturbations in the solar wind that accompany the structure.
Last Modified: 06/18/2019
Modified by: Joseph Borovsky
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