The electric field is easily computed once we have the solution of the static Poisson equation or the NSP equation. The definition of the electric field is as follows

(6.10) |

So, in the context of finite-difference approximations, we compute the electric field in the various cells of the grid as follows

(6.11) | |||

(6.12) |

These simple expressions are used in

Didier Link 2007-05-18