Figure 4: Displacement (a) and (d), strain (b) and (e), and strain (c) and (f) are shown at the two ends of the transducer. Transverse coordinate is relative to the fiber radius . Scaling is arbitrary. The normalized frequency is . Red () and green () curves are for unit reflectivity of the mode back towards with phase . Blue curve is for zero reflectivity and the same transducer amplitude . (a), (b), (c), and (d) show the real parts, corresponding to times when . (d), (e), and (f) show the imaginary parts, corresponding to times when . High-frequency oscillations in some of the curves are a numerical artifact. Since in the absence of reflection has opposite signs at and , the right-hand green plots have been multiplied by minus 1 for better comparison with the blue plots.