Conventional gasdynamic laser performances have been essentially, to an order-of-magnitude, improved by using selective thermal pumping and downstream mixing of the working medium components. Numerical calculation simulation and shock tube modeling data on mixed flow gasdynamic laser operation and its basic characteristics are summarized and discussed. The influence of flow mixing gasdynamics, wave disturbances and resonance self-absorption effects on the performance, gain and power characteristics of a mixed flow GDL is particularly examined and discussed