Numerical study of the parameters of a lowdensity plasma that absorbs CO2 laser radiation
Abstract
The heating and motion of a lowdensity helium plasma heated by pulsed CO2 laser radiation is studied numerically by solving the equations of twodimensional timedependent gasdynamics. The absorption of laser radiation is taken into account, along with nonequilibrium ionization processes, possible departures from thermodynamic equilibrium, the possible effect of electron heat conduction, and selffocusing of the laser radiation. A total laser energy of 10 J, a laser emission frequency of 0.116 eV in energy units, and a pulse length 100 ns are assumed, as well as a mean charged particle density of about 10 to the 18th per cu cm, a maximum ion temperature of 25 eV, and a plasma size of 0.21.2 cm. The results obtained show that: (1) the motion of the plasma produced is substantially twodimensional; (2) the difference between the electron and ion temperatures is considerable; (3) nonequilibrium ionization occurs only in regions with a very low charged particle concentration or at low electron temperatures, i.e., below 12 eV; (4) the effect of electron heat conduction becomes pronounced at electron temperatures higher than 2030 eV; and (5) laser beam propagation becomes substantially nonlinear at electron densities higher than 30%60% of a critical value that depends on the laser emission frequency.
 Publication:

PMTF Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki
 Pub Date:
 January 1981
 Bibcode:
 1981PMTF...21...35P
 Keywords:

 Carbon Dioxide Lasers;
 Laser Plasma Interactions;
 Photoabsorption;
 Plasma Heating;
 Rarefied Plasmas;
 Electron Density (Concentration);
 Gas Dynamics;
 Helium Plasma;
 Laser Heating;
 Pulsed Lasers;
 Plasma Physics