PERIODIC-RESPONSE OF THE BLOCH EQUATIONS TO A PULSE-TRAIN - AN APPLICATION TO MESOSPHERIC SODIUM

The post-transient response of the Bloch equations subject to a periodic pulse train is investigated. This is accomplished by representing all time-dependent variables in their Fourier series with time independent expansion coefficients. Inserting these expansions into the Bloch equations results in a matrix equation which is easily solved. In order to check the validity of this code a square pulse analytic piecewise solution is developed for the relaxation times much longer than the pulse width. Several comparative examples are given for scattering in mesospheric sodium when it is approximated as a two-level atom with short pulse gaussian and square wave envelopes.