“…(1) and (2), the finite-difference method (FDM) has often been used, particularly in early studies (e.g., [6,9]). However, to more accurately compute the near wire region characterized by strong gradients, other approaches have been developed: non-Cartesian FDM [8] and methods which can use unstructured grids, such as the finite-element method (FEM) [10,13] or the finite-volume method (FVM) [11]. Moreover, FEM, which is well adapted to the solution of the elliptic Poisson equation, can be combined with methods suitable for the hyperbolic equation, e.g., FEM-FDM [7], FEM-FVM [12], FEM, and method of characteristics [19,20] (for a review see [11]).…”