Intercomparison of In Situ Electric Fields in Human Models Exposed to Spatially Uniform Magnetic Fields

IEEE C95.1 (radio frequency) and C95.6 (low frequency) standards for human protection from electromagnetic fields are currently under revision. In the next revision, they will be combined into one standard covering the frequency range from 0 Hz to 300 GHz. Although the C95.1 standard considers anatomical human models for deriving the relationship between internal and external field strengths, homogeneous ellipses are used in the C95.6 standard. In the guidelines of the International Commission on Non-Ionizing Radiation Protection, anatomical human models are used together with reduction factors to account for numerical uncertainty. It is worth revisiting their relationship when using different anatomical models. In this paper, five research groups performed a comparative study to update the state-of-the-art knowledge of in situ electric fields in anatomical human models when exposed to uniform low-frequency magnetic fields. The main goals were to clarify both numerical uncertainty and model variability. The computational results suggest a high consistency among in situ field strengths across laboratories; agreement in the 99th percentile with a discrepancy of under 5% was achieved. The in situ electric fields varied as expected given the models' different dimensions. The induction factor, which is the ratio of the in situ electric fields for the temporal derivative of the external magnetic flux density, is derived for body parts and tissues. The classification of body parts into "the limb" and "other tissues" is shown to be critical for determining the in situ field strength.