Figure 4.

Peak positive and peak negative pressure distributions along the z-axis (a) and in the focal plane (b) along the y-axis (x = 0). The distributions are calculated for linear beam focusing (1) and for nonlinear focusing for initial intensity at the array elements I₀ = 1 W·cm⁻² (2), I₀ = 5 W·cm⁻² (3), and I₀ = 10 W·cm⁻² (4). The distributions are normalized by the initial pressure amplitude p₀ = ρ₀c₀V₀.