An optimal 5-point scheme for frequency-domain scalar wave equation

• A new 5-point scheme is proposed for 2D frequency-domain scalar wave equation.
• Optimal finite-difference coefficients are obtained by conjugate gradient method.
• The new scheme provides much greater accuracy than the classic one.

The classic 5-point scheme has been commonly applied in frequency-domain finite-difference (FD) modeling and full waveform inversion of 2D scalar wave equation. This scheme takes less computational costs but provides pretty lower accuracy than other more-point schemes. To improve the accuracy without increasing computational costs of this scheme, I develop a new 5-point scheme. Taylor-series expansion (TE) and conjugate gradient (CG) methods are adopted to calculate FD coefficients respectively. Dispersion analysis shows that the new scheme provides significantly greater accuracy than the classic one, and the CG-based new scheme generally has higher precision than the TE-based new one. Numerical experiments demonstrate the advantage of the proposed scheme.