Channeling of an Ionizing Electrical Streamer by a Laser Beam

Long electrical spark discharges have been directed through air along predetermined paths defined by a concentrated laser beam. At apparent optical power densities of 50–100 giga W/cm2, 35-nsec half-width laser pulses at 10 600 Å have been effective in channeling streamer discharges from a 350-kV positively charged electrode for distances up to 28 cm in a total streamer length of 71 cm. The average E field required to obtain a discharge between electrodes was reduced from 7.3 to 5.5 kV/cm with the laser powers employed.