Instabilities in Laser Propagation in Fluids
Abstract
Instabilities in the system of equations describing electromagnetic wave propagation and fluid dynamics are discussed. The basic equations are discussed, and the linearized stability analysis is presented along with an evaluation of the threshold for these growing waves. To follow the growth of the disturbances, computer studies were undertaken. In the course of these studies it became apparent that there was some merit to introducing a new concept to judge the value of an algorithm for computing the solutions of a system of partial differential equations. This concept was called 'utility', and is discussed along with several examples of its application to simpler partial differential equations. Presented are the results of a calculation of beam distortion for a very high intensity pulse propagating through air for several kilometers. In the attempt to calculate distortions of the type predicted by the linearized instability analysis, cylindrical symmetry was imposed on the problem in order to facilitate the computer calculation. The report contains an analytic discussion of beam bending and thermal blooming for a slab beam propagating through a wind. A formula is derived which provides for the transition between two regimes in which conduction and forced convection, respectively, dominate the dissipation of heat deposited in the medium from the laser beam.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1970
- Accession Number
- AD0718858
Entities
People
- William G. Wagner
Organizations
- University of Southern California