| NSF Org: |
AGS Division of Atmospheric and Geospace Sciences |
| Recipient: |
|
| Initial Amendment Date: | August 31, 2017 |
| Latest Amendment Date: | August 31, 2017 |
| Award Number: | 1723416 |
| Award Instrument: | Standard Grant |
| Program Manager: |
John Meriwether
AGS Division of Atmospheric and Geospace Sciences GEO Directorate for Geosciences |
| Start Date: | September 1, 2017 |
| End Date: | August 31, 2021 (Estimated) |
| Total Intended Award Amount: | $360,000.00 |
| Total Awarded Amount to Date: | $360,000.00 |
| Funds Obligated to Date: |
|
| History of Investigator: |
|
| Recipient Sponsored Research Office: |
4765 WALNUT ST STE B BOULDER CO US 80301-2575 (720)974-5888 |
| Sponsor Congressional District: |
|
| Primary Place of Performance: |
4750 Walnut Suite 205 Boulder CO US 80301-2532 |
| Primary Place of
Performance Congressional District: |
|
| Unique Entity Identifier (UEI): |
|
| Parent UEI: |
|
| NSF Program(s): | SOLAR-TERRESTRIAL |
| Primary Program Source: |
|
| Program Reference Code(s): |
|
| Program Element Code(s): |
|
| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
This SHINE Investigation focuses on the production of stellar winds and will provide information about the physics of double layers in natural plasmas. Stellar winds production is important for other astrophysical systems as well as understanding the solar wind that the Earth and other planetary systems are subject to. The Principal Investigator in acts as a SHINE-GEM Liaison where solar/solar-wind issues and geospace issues are communicated between two research communities and is active in the Los Alamos Space Weather Summer School where his research investigations have been used to create student research projects.
This 3-year SHINE Investigation will make improvements to the physics of exosphere models of the solar wind and will determine how those improvements affect the properties of the solar wind and the exobase that drives it. The major advance will be to replace a static (in the Sun's reference frame) interplanetary potential with a potential made up of multiple weak double layers propagating in the solar wind plasma. The changed reaction of ions to moving potential structures (instead of a Sun-stationary potential structure) will result in: (1) changed terminal velocities for the protons and heavy ions as a function of the electron velocity distribution function at the exobase, (2) a related change in the total electrostatic potential needed to accelerate the solar wind, (3) heating, rather than cooling, of the ions as they are accelerated, (4) differences in the outward acceleration of protons and heavy ions. Using multiple double layers as the form of the potential in exosphere models for the interplanetary electric field will result in a more-physically correct model and should overcome several of the shortcomings that existing exosphere models have. As a fundamental part of this SHINE project, PIC plasma simulations will be run to discern critical properties of solar-wind double layers as inputs to the exosphere model.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
Note:
When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external
site maintained by the publisher. Some full text articles may not yet be available without a
charge during the embargo (administrative interval).
Some links on this page may take you to non-federal websites. Their policies may differ from
this site.
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 SHINE grant was the primary support for several studies that investigated the electron-driven interplanetary electrical potential. The heliospheric magnetic field has a spaghetti structure comprised of a tangle of magnetic flux tubes: one major finding of this SHINE investigation was that the core electron temperature of the solar wind varies from flux tube to flux tube. This indicates that the electrical potential varies from flux tube to flux tube. Rather than there being a global interplanetary potential that drives the solar wind flow, the interplanetary potential appears to act locally in each magnetic flux tube independently from the other flux tubes. A second study looked at variations of the energetic-electron strahl from flux tube to flux tube to establish that the flux-tubes of the magnetic spaghetti are coherent from 1 AU back to the Sun. A third study utilized the findings of the second study to further examine the energetic-electron strahl observations in the near-Earth solar wind to develop statistics about the magnetic connection of the Earth to the Sun when the Earth is in various types of solar-wind plasma. A fourth study looked at the magnetic connection of the Moon to the Sun and examined the possibility of extreme electrical charging on the darkside surface of the Moon during the early phases of solar energetic electron events, which are common during the maximum phase of the solar cycle. A fifth study examined the nature of the Alfvenic fluctuations in the solar wind that propagate out from the Sun that made careful comparison of the solar-wind fluctuations with turbulent fluctuations in fluids. The writing of three review articles was supported by this SHINE grant. A review article was written that examined observations of the solar wind magnetic field, electrons, and ions at 1 AU to determine which features in the solar wind at 1 AU are fossils from the Sun and which features could have been created in situ away from the Sun. A second review focused on the properties of the solar-wind magnetic spaghetti as seen in measurements of the magnetic field, the ions of the solar wind, the electrons of the solar wind, and the energetic electrons of the solar wind. Finally, this SHINE grant supported the writing of an AGU Centennial review that outlined the outstanding questions of solar-wind physics. In all, this SHINE grant was the primary support for 8 scientific publications.
Last Modified: 12/30/2021
Modified by: Joseph Borovsky
Please report errors in award information by writing to: awardsearch@nsf.gov.
