To numerically solve the wave equation of the magnetic vector potential in the x-y plane, one should start with the identity "curl squared = grad div - del squared," leading to Laplace's equation under the gauge condition ∇·A = 0. The resultant equation ∇^2 A = -µ J indicates that A is a vector, necessitating the solution of its components separately in Cartesian coordinates, resulting in three Laplacian equations. The components Ax, Ay, and Az can be placed at grid nodes, but alternative grid setups, such as the Yee grid used in FDTD methods, may also be suitable. The discussion highlights the importance of choosing a stable numerical method for discretizing the magnetic field potential in the x-y-z plane. Examples of discretization techniques and relevant literature are sought for further guidance.