Illustration of the changes to radial profiles of disk mass (middle) and surface density (right) due to ten transient spiral waves (left) after one dynamical time. The spiral potentials in the leftmost panel are modeled as Gaussians centered on radius R_g with width ΔR_g. The gray scale of each line varies with ΔR_g, from low (light gray) to high (black). The narrowest of these represents the growth in the adiabatic limit, while progressively larger ΔR_g illustrate the result of near-resonant, nonadiabatic growth. Each potential is used to calculate C_g according to Eq. (45). The mass and surface density evolution is calculated according to Eqs. (48) and (51), respectively. The adopted spiral properties are shown in the legend in the rightmost panel.