title: A modeling approach to predict acoustic nonlinear field generated by a transmitter with an aluminum lens.
abstract: OBJECTIVE
  In this work, the authors propose a modeling approach to compute the nonlinear acoustic field generated by a flat piston transmitter with an attached aluminum lens.
  
  
  METHODS
  In this approach, the geometrical parameters (radius and focal length) of a virtual source are initially determined by Snell's refraction law and then adjusted based on the Rayleigh integral result in the linear case. Then, this virtual source is used with the nonlinear spheroidal beam equation (SBE) model to predict the nonlinear acoustic field in the focal region.
  
  
  RESULTS
  To examine the validity of this approach, the calculated nonlinear result is compared with those from the Westervelt and (Khokhlov-Zabolotskaya-Kuznetsov) KZK equations for a focal intensity of 7 kW/cm(2). Results indicate that this approach could accurately describe the nonlinear acoustic field in the focal region with less computation time.
  
  
  CONCLUSIONS
  The proposed modeling approach is shown to accurately describe the nonlinear acoustic field in the focal region. Compared with the Westervelt equation, the computation time of this approach is significantly reduced. It might also be applicable for the widely used concave focused transmitter with a large aperture angle.
authors: Institute of Acoustics, Key Laboratory of Modern Acoustics, MOE, Nanjing University, Nanjing 210093, China.
authors: Tingbo
authors: T
authors: Fan
authors: Zhenbo
authors: Z
authors: Liu
authors: Tao
authors: T
authors: Chen
authors: Faqi
authors: F
authors: Li
authors: Dong
authors: D
authors: Zhang
mesh_terms: D000162:Acoustics; D000535:Aluminum; D004560:Electricity; D057086:High-Intensity Focused Ultrasound Ablation / Q000295:instrumentation*; D007909:Lenses; D017711:Nonlinear Dynamics
chemical_list: D000535:Aluminum