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Magnetic field power spectra and magnetic radial diffusion coefficients using CRRES magnetometer data
Author(s) -
Ali Ashar F.,
Elkington Scot R.,
Tu Weichao,
Ozeke Louis G.,
Chan Anthony A.,
Friedel Reiner H. W.
Publication year - 2015
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2014ja020419
Subject(s) - magnetometer , noon , earth's magnetic field , physics , magnetic field , diffusion , spectral density , van allen radiation belt , spectral line , magnetosphere , computational physics , atmospheric sciences , astronomy , statistics , mathematics , quantum mechanics , thermodynamics
We used the fluxgate magnetometer data from Combined Release and Radiation Effects Satellite (CRRES) to estimate the power spectral density (PSD) of the compressional component of the geomagnetic field in the ∼1 mHz to ∼8 mHz range. We conclude that magnetic wave power is generally higher in the noon sector for quiet times with no significant difference between the dawn, dusk, and the midnight sectors. However, during high K p activity, the noon sector is not necessarily dominant anymore. The magnetic PSDs have a very distinct dependence on K p . In addition, the PSDs appear to have a weak dependence on McIlwain parameter L with power slightly increasing as L increases. The magnetic wave PSDs are used along with the Fei et al. (2006) formulation to computeD LL B [ CRRES ] as a function of L and K p . The L dependence ofD LL B [ CRRES ] is systematically studied and is shown to depend on K p . More significantly, we conclude thatD LL E is the dominant term driving radial diffusion, typically exceedingD LL Bby 1–2 orders of magnitude.