Visualization of Electric Fields Around a Biological Body

A system was developed which can visualize the spatial distribution of the ELF (extremely low frequency) electric field around an object with a complex shape such as a biological body. To minimize the field perturbation, an optical field sensor was used. A mechanical X-Y scanner controlled by a microcomputer moves the sensor, automatically scanning the space around the object. The measured data are processed and the field distribution is represented in a color distribution pattern. Using an object with a simple shape such as a cylinder, the accuracy of the measurement was confirmed by comparison to a numerical calculation. The field distributions around experimental animals (a rat and a cat) were measured and it was shown that a conductor model can be used instead of a living body in the ELF range. The field distribution around a human model could be measured in various postures. The results were compared to those of the measurement with a real human body standing under transmission lines, and reasonable agreement was obtained. This technique will provide useful information for the study of the biological effects of the electric field.