A computer model simulating the formation of an artificially ionized layer in the atmosphere by a series of microwave pulses was developed and is presented. A modified version of the kinetic theory of the breakdown of air by a powerful microwave emission was incorporated into a model of electromagnetic propagation through the atmosphere by a converging ionizing microwave pulse. This model takes into consideration radio wave self-action as well as absorption and produces profiles of electron concentration formed in the atmosphere by both an isolated pulse and a series of pulses. Effects of varying the shape of the ionizing pulse are considered as well as the influence of the ambient electron concentration. Also, the dependence of the electron concentration on the energy and duration of the pulse is investigated. The possible increase in the rate of electron production is considered when using an intense pulse to initiate the breakdown followed by a series of pulses of lesser energy. The influence of the refraction of the microwave beam is estimated. The computer model presented shows that an artificial ionized layer of electrons reaching concentrations of the order of 108 cm-3 could be formed over a height range of 40--70 km, if the Arecibo antenna and radio facility were reconfigured so that it would be able to generate microwaves with f=2.38 GHz and a power of approximately 1--4 MW. In addition, a pulse compressor would be used to form pulses with durations of approximately 0.1--0.15 μs with a repetition frequency of 103 Hz. ¿ American Geophysical Union 1993