High-order Time Accuracy Fractional Laplacian Viscoacoustic Simulation Scheme Using Nonstandard Pseudospectral Method

Abstract

Summary The decoupled fractional Laplacian (DFL) is attractive for developing stable Q-compensated RTM because it can compensate independently for either amplitude loss or velocity dispersion. A common numerical method of DFL is pseudospectral (PS) method, in which the fractional spatial derivatives are calculated by FFT, and the time derivative is computed by finite-difference (FD) method. But the FD time discretization will inevitably lead the time stepping errors. In this paper, we propose two nonstandard pseudospectral (NSPS) schemes to compensate the time stepping errors. Stability analysis and several simulation examples show that the proposed NSPS schemes enjoy better accuracy and stability than traditional PS method.