TITLE:
Minimum Attenuation of Physiologically-Patterned, 1 µTesla Magnetic Fields through Simulated Skull and Cerebral Space
AUTHORS:
Michael A. Persinger, Kevin S. Saroka
KEYWORDS:
Time-Varying Magnetic Fields; Penetrability of the Skull; Attenuation Factors; Physiological Concentrations of Ions; 1 MicroTesla Magnetic Fields
JOURNAL NAME:
Journal of Electromagnetic Analysis and Applications,
Vol.5 No.4,
April
11,
2013
ABSTRACT: To answer the queries concerning penetrability of ~1 μT,
physiologically patterned, time-varying magnetic fields through the cranium,
the proportions of attenuation through thicknesses and densities of ~3 times
that of the human skull were measured directly. There was no reduction in the
intensity of the magnetic field when two 2 cm thick dried pine boards
(4.3 × 103 kg·m-3) were placed between
the pairs of solenoids separated by the approximate width of the skull.
Although volumes of water containing intracellular concentrations of ions did
not attenuate the field intensity, placement of 290 cm2 of 2 mm sheets of duct metal
reduced the amplitude by 25%. Spectra comparisons showed a clear congruence in
profiles between direct measurement of the applied field and the original
computer-generated pattern. These results indicate there is little validity to
claims that weak, time-varying magnetic fields applied in this manner are
eliminated or significantly attenuated by the human skull.