I am solving the simple poisson equation $$-\nabla \cdot (\epsilon\nabla u) = \rho$$ using a finite element mesh (rho is just a point charge). I would like to implement a boundary condition such that $$\lim_{r \to \infty} u(r) = 0$$ Is it possible to implement this boundary condition? I.e. Can I place a boundary condition on the boundary of the mesh that will simulate the above limit?
Thanks