Award Abstract # 1261659
New Techniques for Interpreting Physical Structures and Turbulence in the Solar Wind

NSF Org: AGS
Division of Atmospheric and Geospace Sciences
Recipient: SPACE SCIENCE INSTITUTE
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 2014 = $250,000.00
FY 2015 = $250,000.00

FY 2016 = $250,000.00
History of Investigator:
  • Joseph Borovsky (Principal Investigator)
    jborovsky@spacescience.org
  • Antonius Otto (Co-Principal Investigator)
  • Stanislav Boldyrev (Co-Principal Investigator)
  • John Podesta (Co-Principal Investigator)
  • Michael Denton (Co-Principal Investigator)
Recipient Sponsored Research Office: SPACE SCIENCE INSTITUTE
4765 WALNUT ST STE B
BOULDER
CO  US  80301-2575
(720)974-5888
Sponsor Congressional District: 02
Primary Place of Performance: Space Science Institute
4750 Walnut
Boulder
CO  US  80301-2532
Primary Place of Performance
Congressional District:
02
Unique Entity Identifier (UEI): KCBXMSFGQGY3
Parent UEI: KCBXMSFGQGY3
NSF Program(s): SOLAR-TERRESTRIAL
Primary Program Source: 01001415DB NSF RESEARCH & RELATED ACTIVIT
01001516DB NSF RESEARCH & RELATED ACTIVIT

01001617DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s): 0000, OTHR
Program Element Code(s): 152300
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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Boldyrev, S., C. H. K. Chen, Q. Xia, and V. Zhdankin "Spectral breaks of Alfvenic turbulence in a collisionless plasma" Astrophys. J. , v.806 , 2015 , p.238
Borovsky, J. E. "Electrical conductivity channels in the atmosphere produced by relativistic-electron microbursts from the magnetosphere" J. Atmos. Solar-Terr. Phys , v.155 , 2017 , p.22
Borovsky, J. E. "Looking for evidence of wind-shear disconnections of the Earth?s magnetotail: GEOTAIL measurements and LFM MHD simulations" J. Geophys. Res. , v.123 , 2018 , p.5538
Borovsky, J. E. "On the origin of the intercorrelations between solar-wind variables" J. Geophys. Res. , v.123 , 2018 , p.20
Borovsky, J. E. "Relativity and the Solar Wind: The Maxwell-Equation Origins of the Solar-Wind Motional Electric Field" J. Electromag. Analy. Applic , v.8 , 2016 , p.133
Borovsky, J. E. "The plasma structure of coronal-hole solar wind: Origins and evolution" J. Geophys. Res. , v.121 , 2016 , p.5055 2016JA022686
Borovsky, J. E. "The spatial structure of the oncoming solar wind at Earth" J. Atmos. Solar-Terr. Phys. , v.177 , 2018 , p.2
Borovsky, J. E. "Time-integral correlations of multiple variables with the relativistic-electron flux at geosynchronous orbit: The strong roles of the substorm-injected electrons and the ion plasma sheet" J. Geophys. Res. , v.122 , 2017 , p.11961
Borovsky, J. E., and J. A. Valdivia "The Earth?s magnetosphere: A systems science overview and assessment" Surveys Geophys. , v.39 , 2018 , p.817
Borovsky, J. E., and J. J. Podesta "Exploring the effect of current-sheet thickness on the high-frequency Fourier spectrum of the solar wind" J. Geophys. Res. , v.120 , 2015 , p.9256
Borovsky, J. E., and J. L. Delzanno "Space active experiments: The future" Front. Astron. Space Sci. , 2019 10.3389/fspas.2019.00031
(Showing: 1 - 10 of 38)

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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