Open AccessA note on two expressions for the spatial power spectrum of the geomagnetic field
Author(s) -
Angelo De Santis,
D. R. Barraclough
Publication year - 1996
Publication title -
annals of geophysics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 60
eISSN - 2037-416X
pISSN - 1593-5213
DOI - 10.4401/ag-3988
Subject(s) - radius , earth's magnetic field , exponential function , power law , physics , spectral density , spherical harmonics , core (optical fiber) , spectrum (functional analysis) , field (mathematics) , earth radius , magnetic field , computational physics , mathematical analysis , mathematics , quantum mechanics , optics , statistics , pure mathematics , magnetosphere , computer security , computer science
The spatial power spectrum of the geomagnetic field is usually assumed to be exponential in the spherical harmonic degree (n). An equally valid assumption, however, is that the spectrum at the surface of the Earth's core has a power-law dependence on n. Some implications of these two assumptions are discussed, noting that, in the first case, a value for the core radius can be derived from the slope of the spectrum and, in the second, that the spectrum for radii greater than the radius of the core is a mixture of the exponential and power-law types