FIG. 5.

(Color online) Setting the boundary condition for modeling the propagation of a nonlinear beam through the human head. The array is the surface of the FPA. Boundary 1 and boundary 2 are the planes of setting the boundary condition for the Westervelt and pseudo-spectral time domain simulations, respectively, of the wave propagation through the water, skin, skull, and brain to boundary 2. Boundary 2 is the plane of setting the boundary condition for nonlinear modeling in deep brain structures using the Westervelt equation. “F” is the focal point.