This report describes a computational model of a copper l=r amplifier. The model contains rate equations for copper and thebuffer gasspecies (neonandhydrogen), alongwithequations fortheelectron temperature, thelaserintensity, andthediffusing magnetic fieldof thedischarge. Ratesaregivenforall pertinent atomicreactions. Theradial profile of thegastemperature isdetermined by thetime-averaged powerdeposited inthegas.Thepresence of septum inserts, whichaidgsscooling, is takenintoaccount. Fieldsarecalculated consistently throughout the plasmaand the surrounding insulation.Employed in conjunction with a modulator model, the model is used to calculate comprehensive performance predictions for a high-power operational amplifier. *.