Comparison of numerical methods for the nonlinear Klein-Gordon equation in the nonrelativistic limit regime
Provides a comprehensive comparison of numerical methods for a specific PDE regime, aiding researchers in selecting appropriate techniques for multiscale wave problems.
This paper systematically compares various numerical methods for solving the nonlinear Klein-Gordon equation in the nonrelativistic limit regime (ε≪1), where wave propagation exhibits multiscale behavior. The multiscale time integrator is used to study convergence rates to limiting models as ε→0+.
Different efficient and accurate numerical methods have recently been proposed and analyzed for the nonlinear Klein-Gordon equation (NKGE) with a dimensionless parameter $\varepsilon\in (0,1]$, which is inversely proportional to the speed of light. In the nonrelativestic limit regime, i.e. $0<\varepsilon\ll1$, the solution of the NKGE propagates waves with wavelength at $O(1)$ and $O(\varepsilon^2)$ in space and time, respectively, which brings significantly numerical burdens in designing numerical methods. We compare systematically spatial/temporal efficiency and accuracy as well as $\varepsilon$-resolution (or $\varepsilon$-scalability) of different numerical methods including finite difference time domain methods, time-splitting method, exponential wave integrator, limit integrator, multiscale time integrator, two-scale formulation method and iterative exponential integrator. Finally, we adopt the multiscale time integrator to study the convergence rates from the NKGE to its limiting models when $\varepsilon\to0^+$.