2018 年 13 巻 p. 1203088
An ingenious model for large-scale plasma simulations is proposed. An artificial permittivity ε∗ much grater than ε0 (permittivity of free space) is introduced to the Poisson equation, ∇· (ε∗∇φ) = −ρ (φ is electrostatic potential and ρ is charge density), and the Debye length is artificially elongated. A large-scale system with a reasonable number of spatial grids can be treated stably even for including the self-consistent electron dynamics. A dielectric tensor is adopted for the three-dimensional global simulation of tokamak plasmas in the cylindrical coordinates (R, θ, Z). A diagonal element εθθ for toroidal axis θ is set much larger than those for the poloidal plane, εRR = εZZ = ε∗. Number of toroidal meshes Nθ can be reduced enough smaller than that of poloidal-plane meshes, NR and NZ, in comparison with Nθ > NR, NZ for the usual case of isotropic ε∗.