National Aeronautics and Space Administration

Living With A Star

Targeted Research and Technology

Physical Processes Responsible for Relativistic Electron Variability in the Outer Radiation Zone over the Solar Cycle

ROSES ID: NRA-03-OSS-01      Selection Year: 2004      

Program Element: Independent Investigation: LWS

Principal Investigator: Richard Thorne

Affiliation(s): UCLA

Project Member(s):
Summers, Danny COI Memorial University of Newfoundland
Bailey, Miesha Authorizing Official University of California Los Angeles
Meredith, Nigel P Collaborator University College London
Horne, Richard Bertram Collaborator British Antarctic Survey


Our basic understanding of the physical processes responsible for the variability of relativistic electrons in response to solar activity is currently incomplete. These extremely energetic electrons have important effects on life and society ranging from the disruption of satellites to the modification of the chemistry of the middle atmosphere and associated effects on climate and the quality of life. As an integral contribution to the LWS program we propose to investigate the basic non-adiabatic processes responsible for the injection, transport and loss of relativistic electrons in the outer radiation zone. Most of the important process that violate the adiabatic invariants involve interactions with various plasma waves. We propose to utilize existing satellite data to characterise the properties of relevant waves and their variability with solar activity, and then use this data base to evaluate diffusion coefficients to describe the non-adiabatic dynamics of relativistic electrons over the solar cycle. This will allow us to quantify the rates of electron acceleration and loss under different geomagnetic conditions, and thus understand why some disturbances lead to electron enhancement while others lead to net loss. This research is is central to NASA's interests in understanding the dynamic response of the near-space environment to solar activity and the coupling between the magnetosphere and the middle atmosphere.


Performance YearReferenceInvestigation TypeActions
1Richard Thorne / UCLA-Physical Processes Responsible for Rel...
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1Summers, D.; Ma, C.; Meredith, N. P.; Horne, R. B.;...
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1Thorne, Richard M.; Horne, Richard B.; Glauert, Sarah...
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1Summers, Danny; Thorne, Richard M.; (2005), Correction t...
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Performance YearReferenceActions
1Thorne, R. M.; O'Brien, P.; Summers, D.; Shprits...

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