Effects of Absorption at 106 μ on Laser-Beam Transmission

A linearized theory of transient laser heating in fluids

“…These effects tend to damp the highspatial frequency perturbations that would otherwise dominate the results obtained from solution of previous approximations [1,2]. The above equation correctly generalizes the sound velocity to include the transition from adiabatic to isothermal compression that occurs for the higher-spatial frequencies.…”

“…The fraction of energy lost to the medium might be a relatively small portion of the total energy, yet sufficient to disturb the medium, creating acoustic waves that may move a significant distance transverse to the propagation direction during the pulse. Such waves lead to the wellknown t -blooming refractive-index variations [1,2]. As the medium attains mechanical equilibrium, a linear time dependence is found -this is referred to as steady-state thermal blooming.…”

“…A third assumption that is often appropriate is that the population transfer has reached a steady state; often the population decay rate is on the order of nanoseconds, during which time the acoustic and dissipative processes in the medium have produced negligible effects [22]. With these assumptions, the more familiar equation [1,2,5] for the medium perturbation is recovered, but in this case dissipative efFects are properly treated:…”

“…With smooth variations of the fiow along the optical propagation path, Eq. (16a) retains its validity[1,2], and this variable-wind case is included in the formalism. The above equation for density variation is supplemented with a similar equation for the entropy perturbation s: our basic equations for transient laser heating.…”

An Analysis of Mathematical Transformations and a Comparison of Numerical Techniques for Computation of High-Energy CW Laser Propagation in an Inhomogeneous Medium

“…This effect can nevertheless be brought into this model without change in the basic nature of the algorithm, since it merely affects a quadrature formula. 1 ' 3 ' 5 We convert the model to a form containing all variables in dimensionless form by letting u -W/(P/ c2) (2-5)…”