Using MEPED observations to infer plasma density and chorus intensity in the radiation belts

William J. Longley; Anthony A Chan; Allison N Jaynes; Scot R Elkington; Joshua M Pettit; Johnathan P. J. Ross; Sarah A Glauert; Richard B Horne

doi:10.3389/fspas.2022.1063329

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Using MEPED observations to infer plasma density and chorus intensity in the radiation belts

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Using MEPED observations to infer plasma density and chorus intensity in the radiation belts

William J. Longley, Anthony A Chan, Allison N Jaynes, Scot R Elkington, Joshua M Pettit, Johnathan P. J. Ross, Sarah A Glauert and Richard B Horne

Frontiers in astronomy and space sciences, Vol.9, 1063329

11/21/2022

DOI: 10.3389/fspas.2022.1063329

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Abstract

Efforts to model and predict energetic electron fluxes in the radiation belts are highly sensitive to local wave-particle interactions. In this study, we use multi-point measurements of precipitating and trapped electron fluxes to investigate the dynamic variation of chorus wave-particle interactions during the 17 March 2013 storm. Quasilinear theory characterizes the chorus wave-particle interaction as a diffusive process, with the diffusion coefficients depending on the particle energy and pitch angle, as well as the background plasma parameters such as the wave intensity and plasma density. These plasma parameters in the radiation belts are spatially localized and time-varying, so we construct event-specific diffusion coefficients using MEPED (onboard POES/MetOp) measurements of electron fluxes at low Earth orbit. This new method provides realistic diffusion coefficients for chorus waves that account for changes in the wave intensity, the plasma density, and the magnetic field strength in the outer radiation belt. We show that the inferred chorus intensity is significantly lower than previous estimates that use MEPED observations since the same amount of increased precipitation by 30-300 keV electrons can be explained by a change in the plasma density. This technique therefore allows for us to create time varying, global maps of the plasma-gyrofrequency ratio (fpe/fce), and therefore plasma density, in the outer radiation belts using the MEPED measurements. The global density estimates compare reasonably well to in situ density measurements from RBSP-B.

Physical Sciences

Astronomy & Astrophysics

Science & Technology

Details

Title: Subtitle: Using MEPED observations to infer plasma density and chorus intensity in the radiation belts
Creators: William J. Longley - Rice University
Anthony A Chan - Rice University
Allison N Jaynes - University of Iowa
Scot R Elkington - University of Colorado Boulder
Joshua M Pettit - Goddard Space Flight Center
Johnathan P. J. Ross - Natural Environment Research Council
Sarah A Glauert - Natural Environment Research Council
Richard B Horne - British Antarctic Survey
Resource Type: Journal article
Publication Details: Frontiers in astronomy and space sciences, Vol.9, 1063329
DOI: 10.3389/fspas.2022.1063329
ISSN: 2296-987X
eISSN: 2296-987X
Publisher: Frontiers Media Sa
Number of pages: 15
Grant note: NNX14AH54G / NASA Living With a Star program; National Aeronautics & Space Administration (NASA) 80NSSC21K1323 / NASA LWS grant AGS 1651428 / NSF; National Science Foundation (NSF) NE/R016445/1 / NERC National Public Good NE/R016038/1 / NERC National Capability NNX17AI51G / NASA H-SR NNX16AK22G / NASA Living With a Star Jack Eddy Postdoctoral Fellowship Program NE/V00249X/1 / NERC; UK Research & Innovation (UKRI); Natural Environment Research Council (NERC)
Language: English
Date published: 11/21/2022
Academic Unit: Physics and Astronomy; University College Courses
Record Identifier: 9984428837902771

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