DIRECTED
ENERGY
PROFESSIONAL
SOCIETYJOURNAL OF DIRECTED ENERGY
DIRECTED
ENERGY
PROFESSIONAL
SOCIETY
JOURNAL
OF DIRECTED
ENERGY
Propagation of Short, High-Intensity Laser Pulses in Air
P. Sprangle,
J. R. Penano,
A. Ting, B. Hafizi,
and D. F.
Gordon
Plasma Physics Division, Naval
Research Laboratory, Washington, D.C. 20375
The atmospheric propagation of
high-intensity, high-average-power laser beams is important for a number of directed
energy applications. Linear as well as nonlinear processes affect atmospheric propagation of short, intense laser pulses. A set of equations for modeling the three-dimensional atmospheric propagation of intense short laser pulses is presented and discussed. The
equations account for the linear propagation effects of dispersion, absorption, scattering,
and turbulence. The nonlinear propagation effects included are transient thermal
blooming, bound electron anharmonicity (optical Kerr effect), stimulated Raman scattering,
ionization, plasma response (wakefields), and relativistic quiver motion. In many
applications nonlinear effects, turbulence, and dispersion are important because of
the short laser pulse durations and high peak intensities. The equations are used
to study the propagation of a single laser pulse with peak power in the gigawatt range.
Examples illustrate several important processes that would be associated with directed
energy applications of intense laser beams, such as a free-electron laser with peak
(average) power in the gigawatt (megawatt) range.
KEYWORDS: Atmospheric propagation, Blooming, Free-electron laser, Turbulence