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National Science Foundation Award #0549093

Quantification of Radial Diffusion in Energizing MeV (Millions of Electron Volts) Electrons in the Magnetosphere

Investigator(s):

Xinlin Li (PI)

Sponsor:

University of Colorado at Boulder, CO 80309 3034926221

Start Date/Expiration Date

2006-04-15 to 2007-03-31 (amended 2006-03-24)

Awarded Amount to Date:

$50,000

Abstract: An important objective of magnetospheric research is the understanding and eventual accurate prediction of the variability of energetic particles in the radiation belts. Electrons in the energy range of a few hundred thousands of electron volts (keV) to a few millions of electron volts (MeV) can have deleterious effects on spacecraft electronics through radiation damage and deep dielectric charging. Though significant progress has been made in predicting MeV electrons at and inside geosynchronous orbit using the radial diffusion model, the quantitative contribution of different physical mechanisms governing the variability of these electrons are still unclear. Previous radial diffusion models have assumed a source population at the outer boundary of the radiation belt, but it has been difficult to confirm the validity of this assumption due to limited observations. This uncertainty also raises the question of the validity of the radial diffusion coefficients and loss rates used. This project will eliminate this uncertainty by using actual measurements of electrons as the source population. This will be accomplished by using data from Los Alamos National Laboratory (LANL) sensors at geosynchronous orbit. The goal is to quantify the contribution of radial diffusion to the acceleration of MeV electrons inside geosynchronous orbit. The project will incorporate realistic loss rates into the diffusion model by using data from the SAMPEX and Polar satellites. The model results inside geosynchronous orbit will be compared to Polar measurements. This comparison will make it possible to determine how much enhancement of MeV electrons can be attributed to radial diffusion. A significant portion of the research will be carried out by a graduate student under the direction of the Principal Investigator.

NSF Org:

ATM - Division of Atmospheric Sciences

Award Number:

0549093

Award Instrument:

Continuing grant

Program Manager:

Kile B. Baker
ATM Division of Atmospheric Sciences
GEO Directorate for Geosciences

NSF Program(s):

MAGNETOSPHERIC PHYSICS

Field Application(s):

Space

Program Reference Code(s):

UNASSIGNED, 0000

Program Element Code(s):

5750