The earth's electromagnetic environment

Martin Fullekrug, Antony C Fraser-Smith

Research output: Contribution to journalArticle

11 Citations (Scopus)
144 Downloads (Pure)

Abstract

It is found that the energy density of electromagnetic fields at the surface of the Earth follow a scaling law that extends over 16 orders of magnitude from 10-9 Hz to 107 Hz. The temporal variability of the field can be described with an 1/f2, or Brownian, noise power spectrum which reflects the superposition of numerous transient source processes. To the best of our knowledge, the spectral extent of this straightforward scaling law is unparalleled and outperforms any other scaling law in physics which describes a time dependent observable. The frequency dependence of the energy density can be approximated with the analytic description u(f) = u0(f0/f)2 where u 0 = 10-16 Jm-3Hz-1, f0 = 1 Hz is a scaling constant, and f is the frequency of the electromagnetic field. The corresponding frequency dependence of the magnetic field is B(f) = B 0(f0/f) where B0 = 10-11 T/Hz 1/2.
Original languageEnglish
Article numberL21807
Number of pages5
JournalGeophysical Research Letters
Volume38
Issue number21
Early online date8 Nov 2011
DOIs
Publication statusPublished - Nov 2011

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