Journal article
Electric and magnetic radial diffusion coefficients using the Van Allen probes data
Journal of geophysical research. Space physics, Vol.121(10), pp.9586-9607
10/2016
DOI: 10.1002/2016JA023002
Abstract
ULF waves are a common occurrence in the inner magnetosphere and they contribute to particle motion, significantly, at times. We used the magnetic and the electric field data from the Electric and Magnetic Field Instrument Suite and Integrated Sciences (EMFISIS) and the Electric Field and Waves instruments (EFW) on board the Van Allen Probes to estimate the ULF wave power in the compressional component of the magnetic field and the azimuthal component of the electric field, respectively. Using L∗, Kp, and magnetic local time (MLT) as parameters, we conclude that the noon sector contains higher ULF Pc‐5 wave power compared with the other MLT sectors. The dawn, dusk, and midnight sectors have no statistically significant difference between them. The drift‐averaged power spectral densities are used to derive the magnetic and the electric component of the radial diffusion coefficient. Both components exhibit little to no energy dependence, resulting in simple analytic models for both components. More importantly, the electric component is larger than the magnetic component by one to two orders of magnitude for almost all L∗ and Kp; thus, the electric field perturbations are more effective in driving radial diffusion of charged particles in the inner magnetosphere. We also present a comparison of the Van Allen Probes radial diffusion coefficients, including the error estimates, with some of the previous published results. This allows us to gauge the large amount of uncertainty present in such estimates.
Key Points
Electric component dominant in driving radial diffusion
Electric and magnetic components exhibit weak dependence on energy
Uncertainty quantification for the total radiation diffusion coefficient
Details
- Title: Subtitle
- Electric and magnetic radial diffusion coefficients using the Van Allen probes data
- Creators
- Ashar F Ali - University of Colorado BoulderDavid M Malaspina - University of Colorado BoulderScot R Elkington - University of Colorado BoulderAllison N Jaynes - University of Colorado BoulderAnthony A Chan - Rice UniversityJohn Wygant - University of MinnesotaCraig A Kletzing - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.121(10), pp.9586-9607
- DOI
- 10.1002/2016JA023002
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Number of pages
- 22
- Grant note
- NASA (NNX15AF59G; NNX14AC04G; NNX13AE39G; NNX15AI93G; NNx14AN55G) NASA Earth and Space Science Fellowship (NESSF) (NNX13AO43H)
- Language
- English
- Date published
- 10/2016
- Academic Unit
- Physics and Astronomy; University College Courses
- Record Identifier
- 9984199723102771
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