静電気放電による発生磁界の火花電圧依存性

抄録

The electrostatic discharge (ESD) of charged metal objects produces electromagnetic (EM) fields having broad-band frequency spectra over the microwave region, which often gives serious EM interference (EMI) to electronic equipment. For the EMI of this kind, it has widely been accepted that the lower spark voltage ESD causes the stronger EMI to high-tech information equipment, whereas its mechanism still remains unknown. On the other hand, we previously proposed a new FDTD algorithm based on gap excitation with the time-variant conductivity and electric field of a spark channel, which enables one to predict the ESD fields due to charged metals having arbitrary shapes. In this study, the spark voltage dependence of the magnetic field due to a spark between cylindrical metals was investigated from our proposed FDTD computation and a spark experiment. As a result, it was found that the lower spark voltage produces the higher magnetic field level, while a certain spark voltage causes the highest magnetic field. This finding implies the presence of an ESD specific condition due to charged metals that gives the highest EM fields.