Steady State Thermal Blooming of Multipulse Laser Beams,
Abstract
Steady state thermal blooming of multipulse laser beams subjected to cross winds is studied in the light of numerical solutions. Enhancement resulting in a 100% increase of the peak irradiance with respect to the non-bloomed but linearly absorbed beam is demonstrated at the optimal pulsing rate. The corresponding gain in terms of spatially averaged power density over the target area containing 85% of total power is 40%. A parametric study is made as a function of three similarity parameters which are sufficient to completely define the problem: the number kappa which is the reciprocal of the number of pulses per flow time, the Fresnel number F based on the absorption-irradiance interaction length scale and the absorption number gamma related to linear depletion. Optimal conditions for a collimated Gaussian beam are shown to exist for 0.8 approximately less than kappa approximately less than 1.0 and F approximately greater than 20. Intensification generally decreases with increasing gamma but only slightly. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1977
- Accession Number
- ADA037218
Entities
People
- L. R. Bissonnette