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Manuscript Title: TLASER - a CO2 laser kinetics code.
Authors: A.R. Davies, K. Smith, R.M. Thomson
Program title: TLASER
Catalogue identifier: ACWD_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 10(1975)117
Programming language: Fortran.
Computer: ICL 1906A.
Operating system: GEORGE 4, SCOPE 3.4, EGTRAN.
RAM: 13K words
Word size: 48
Keywords: Laser physics, Laser model, Dissociation, Power output, Co2.
Classification: 15.

Revision history:
Type Tit le Reference
adaptation 0001 INJLOK See below

Nature of problem:
TLASER is a program which predicts the output power pulse and gain from a model of an electrically excited CO2 gas laser, including the effects of dissociation and a variable ambient gas temperature. The laser medium consists of CO2, N2, He, and CO, the latter being introduced intentionally, or by dissociation of CO2.

Solution method:
The laser medium is described by 8 main dependent variables, E, E1, E2, E3, E4, E5, Iv, N100 which represent respectively the energy of the translational plus rotational motion of the gas, the energies of the three vibrational modes of CO2, the energies of the vibrational modes of N2 and CO, the radiation intensity within the laser cavity and N100 P(J+1) is the number of CO2 molecules per unit volume in the rotational level J(J+1) of the lowest symmetric mode. The model consists of eight coupled ordinary differential equations, each describing the rate of change of one of the above variables with time. These equations are solved initially by the Runge-Kutta method and subsequently by a modified Hamming predictor corrector method.

Restrictions:
The model used is a spatially independent one. Only the dominant energy exchange processes have been included and there is no analysis of the plasma properties other than these energy exchange processes. The degree of dissociation of CO2 is input as data. Either an analytic shape is assumed for the electron beam describing the number of electrons per unit volume as a function of time or experimental values can be read in.

Running time:
Execution time for a complete solution of the power output profile over 1 mu s takes typically 7 s on a CDC 6600 and 7 min on a KDF9.

ADAPTATION SUMMARY
Manuscript Title: INJLOK: a CO2 laser injection locking code.
Authors: A.R. Davies, K. Smith, R.M. Thomson
Program title: 0001 INJLOK
Catalogue identifier: ACWD_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 20(1980)413
Programming language: Fortran.
Classification: 15.

Nature of problem:
The adapted code models the effect of an injected low-power frequency- stable signal on a high power CO2 laser. The intensity and frequency of the output from the high-power laser is calculated.

Solution method:
The original program has been changed by substituting for the cavity field intensity equation, a set of equations describing the transient behaviour of the different mode field amplitudes and phases.

Restrictions:
The intensity of the injected signal is constant in time

Running time:
For the test case provided the running time is 90 s on the Leeds 1960A and 16 s on the ULCC CDC 6600.