Accession Number : AD0776329

Title :   Turbulent Heating of an Atmosphere by a Laser Beam.

Descriptive Note : Research and development technical rept.,


Personal Author(s) : Collett,Edward ; Tchen,Chan Mou

Report Date : FEB 1974

Pagination or Media Count : 32

Abstract : A dynamical theory for the heating of a turbulent medium by a high energy laser is developed. Considered as a heat source, the laser beam is given as a known function of time, position, and of the turbulent state of the medium. The equation of turbulent heating is formulated by investigating the correlation between the fluctuations in velocity, temperature, and the electric field. Based upon Tchen's cascade theory of turbulence, and expression for the eddy conductivity is obtained and represents the contribution by eddies of smaller scales then the mean width of the variable temperature profile. The time evolution of the temperature profile is determined, including the special cases of laser pulses of infinitesimal and finite durations and a cw laser beam. The analysis shows that the effect of turbulence is to increase the standard deviation (or thermal spread) of the mean temperature profile, and thereby decrease the temperature near the beam width. The time and space evolutions of heat conduction are shown to be convertible. (Author)

Descriptors :   *Atmospheres, *Heating, *Laser beams, Turbulence, Atmospheric motion, Heat flux, Eddy currents

Subject Categories : Atmospheric Physics
      Lasers and Masers

Distribution Statement : APPROVED FOR PUBLIC RELEASE