Abstract

Many short-circuit faults on power-transmission lines in Japan are caused by lightning on the Sea of Japan in winter. There are many nuclear power stations on which large cities depend for a large part of their electricity. Lightning faults can paralyze the power transmission lines and these cities. The idea of laser-triggered lightning as an active remedy for this problem was first proposed by Ball in the 1970’s.¹ Figure 1 shows a schematic diagram of a laser-triggered lightning system consisting of a CO₂ laser, focus optics, and a lightning tower to protect power transmissions lines.² Laser light produced by a CO₂ laser is focused on the top of the lightning tower. Focusing optics consist of a Cassegrain-type-focusing telescope. Focused laser light produces plasmas, whose cores are aerosols or air molecules. When a winter thunderstorm occurs, the enhanced electric field at the top of the lightning tower reaches a maximum of about 1000 kV/m. Under this condition, a leader initiating from the top of the tower propagates through the plasma channels with the help of the electric field.

© 1995 Optical Society of America