OBSERVATION OF ELF/ULF SIGNALS ASSOCIATED WITH LIGHTNING EVENTS AT MT. OGAMI IN WINTER

摘要

A positive GC lightning event in winter was detected by a Rogowski coil at Mt. Ogami, Niigata Prefecture, Japan. . The peak current and the electric charge were 26 kA and about 1 kilo-coulomb, respectively. Although only pulse series' were radiated in LF, a horizontal magnetic field waveform resembling the current waveform was observed in ELF at a distance of 296 km. At that distance, because the ELF signal is mostly composed of the induction components, the waveform resembles that of the source current. The signal has potential to estimate the current waveform in relation to the electric charge causing damage to grounded structures.