ABSTRACT
Time-varying magnetic fields induce eddy currents in conductive media. Since the human body at low frequency is almost purely conductive, the exposure to magnetic fields must be limited. Safety standards and guidelines provide limits both for magnetic fields and the induced quantities (e.g. current density or electric field). The former are measurable whereas the latter can be assessed only by means of a dosimetric analysis based on numerical models. For this reason, a two-stage approach is always recommended: first, the measurement of the external magnetic field is performed; second, if the limits are exceeded, the dosimetry assessment is carried out. Since the dosimetric analysis is not straightforward, if the magnetic field exceeds the maximum permissible value, mitigation techniques can be adopted to lower the magnetic field. The literature provides solution as the source management (i.e. change in the source layout), passive shields (metallic plates or passive loops) and active loops. This chapter will go through all these aspects providing a complete overview of the problem.
