An equivalent skin conductivity model for low-frequency magnetic field dosimetry

In this paper, open issues pertaining to the modeling of skin, i.e., a potential target tissue for peripheral nerve stimulation due to low-frequency magnetic field exposure, are addressed. First, an equivalent conductivity for a single-layer skin model is derived using a multi-layer skin structure. Unlike previous works, where the conductivity of the stratum corneum or of a weighted average between several skin layers were employed, the conductivity value of the dermis is found to conservatively estimate the peak electric field induced in the stratum basale (i.e., where Merkel nerve endings start to emerge). Then, the induced fields inside a high-resolution anatomical model using the proposed skin conductivity are compared with the basic restrictions provided by the existing guidelines and safety standards. The analysis of the obtained results shows that the relationship between the basic restrictions and the reference or maximum permissible exposure levels recommended by these safety standards is not always consistent.