Quantitative Evaluation of the Effect of Human Body Exposure to Indirect Lightning Electromagnetic Field

Lightning discharge generates strong electromag-netic fields in its striking vicinity and these fields causes unde-sirable interactions and coupling effects inside the human body. Most of the existing studies address the interaction adopting an antenna model of human body using thin radius approximation and this limits the evaluation scope of electromagnetic coupling on body. Hence this paper studies the effect of exposure of human body to electromagnetic fields generated by a lightning discharge using three dimensional modeling approach. A parallelepiped model of a homogeneous human body is adopted, and the field coupling due to lightning stroke at different strike distances is evaluated using the time domain finite integration technique embedded in CST studio suite software. The LEMF coupling on the body is studied by obtaining the field distribution profile and then computing the coupling parameter Specific Absorption Rate. The obtained values are then compared for the first time to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) standard levels of electromagnetic exposure. A peak transient electric field of 60 k V/m and magnetic field of 89 A/m is observed inside the human body at the lightning current peaking instant when lightning strikes at a 50m distance. Moreover, the electric field exposure level decreases by an average of 10% for the person inside the building structure, and the position of the person affects the exposure level with an average increase of 20 % with the change from the center position to corner.