Q1. What are the contributions in "Paraxial geometrical optics for quasi-p waves: theories and numerical methods" ?
Based on a paraxial eikonal equation satisfied by the traveltime corresponding to the quasi-P downgoing waves, two new advection equations for take-off angles provide essential ingredients for computing amplitude functions on uniform Cartesian grids.
Q2. What are the future works mentioned in the paper "Paraxial geometrical optics for quasi-p waves: theories and numerical methods" ?
To treat the upwind singularity at the point source, the authors extend the adaptive gridding approach originally designed for isotropic solids to anisotropic solids.