Research on the Electrical Breakdown of Gases under Intense Optical Illumination
Abstract
A theoretical and experimental research program has been conducted on the physical mechanisms associated with the electrical breakdown of gases under the intense optical illumination from a laser. The light beam from a ruby laser was focused to a small region in the center of a test cell to ionize helium, argon, and air. Breakdown in air required the highest field strengths, the next highest were required to ionize helium, and the lowest field strengths were required for argon. Theoretical studies have indicated that the inverse Bremsstrahlung process, involving the absorption of optical photons by free electrons during collisions with gas atoms, satisfactorily accounts for the high degree of ionization produced during the short laser pulse and, in addition, predicts the observed pressure dependence of the breakdown. It was observed that as much as 50% of the total energy in the laser beam was absorbed in the plasma produced by breakdown and ttenuations by as much as a factor of 10 were observed in the intensity of the laser beam at later times in the optical pulse. An extension of inverse Bremsstrahlung to the fully ionized case shows considerable promise as the process to account for this absorption. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 27, 1964
- Accession Number
- AD0428206
Entities
People
- A. F. Haught
- R. G. Meyer Jr.
Organizations
- United Technologies Corporation