TITLE:
Numerical Investigation of the Tri-Atomic Ions Formation during Laser Ionization Based on Resonance Saturation
AUTHORS:
M. A. Abdelati, M. A. Mahmoud, Y. E. E. Gamal
KEYWORDS:
Plasma, Laser, Collisional Ionization, Association Ionization, Tri-Atomic Ions, Photoionization, Electron Energy Distribution Function
JOURNAL NAME:
Journal of Applied Mathematics and Physics,
Vol.2 No.12,
November
25,
2014
ABSTRACT:
We present a theoretical investigation of
plasma generation in sodium vapor induced by laser radiation tuned to the first
resonance line (3S-3P) at λ = 589 ns. A set of rate equations that describe the
rate of change of the ground and excited states population as well as the
temporal variation of the electron energy distribution function (EEDF), beside
the formed atomic ion Na+, molecular ion
and tri-atomic ions
are solved numerically. The calculations are carried out at
different laser energy and different sodium atomic vapor densities under the
experimental conditions of Tapalian and Smith (1993) to test the existence of
the formed tri-atomic ions. The numerical calculations of the electron energy
distribution function (EEDF) show that a deviation from the Maxwellian
distribution due to the super elastic collisions effect. In addition to the competition
between associative ionization (3P-3P), associative ionization (3P-3D) and
Molnar-Horn- beck ionization processes for producing
, the calculations have also shown that the atomic ions Na+
are formed through the Penning ionization and photoionization processes. These
results are found to be consistent with the experimental observations.