Figure 2: Plot of the optimal trajectories (left) and of the inversion recovery sequence (right) in the plane . Experimental parameters are taken to be ms, ms, and Hz. The experimentally measured trajectories are represented by filled squares and open diamonds. In the upper panel, the small insert represents a zoom of the optimal trajectory near the origin. The dotted line is the switching curve originating from the horizontal singular line. The solid curve is the optimal trajectory near the origin. The lower panel displays the corresponding control laws. is the reduced time defined by .