The present letter demonstrates that significant population inversion can be achieved in the flow structure behind a blast wave if appropriate choice of the initial parameters is made. Typical numerical results are given for a cylindrical blast from a line source in a CO2&sngbnd;N2&sngbnd;He medium. The predicted peak population inversion levels are an order of magnitude better when compared with those achieved in the more conventional gas‐dynamic expansion systems using supersonic nozzles.