Potential-Density Basis Sets for Three-Dimensional Disks

Poisson's equation, ∇ 2 ψ = 4π G ρ, can be solved approximately using basis sets of potential-density pairs. A given density is approximated by a truncated expansion; the computed expansion coefficients immediately yield the corresponding potential since each basis density function is paired with a basis potential function, and Poisson's equation is linear.