Multisymplectic Fourier pseudo-spectral integrators for Klein-Gordon-Schrodinger equations

A multisymplectic Fourier pseudo-spectral scheme, which exactly preserves the discrete multisymplectic conservation law, is presented to solve the Klein-Gordon-Schrodinger equations. The scheme is of spectral accuracy in space and of second order in time. The scheme preserves the discrete multisymplectic conservation law and the charge conservation law. Moreover, the residuals of some other conservation laws are derived for the geometric numerical integrator. Extensive numerical simulations illustrate the numerical behavior of the multisymplectic scheme, and demonstrate the correctness of the theoretical analysis.