It is straightforward to compute the scalar product between dipole and electrical field vector
as soon as the field components of the latter are known. They are computed
in the beginning of the simulation and are stored in tables.
The explicit derivaton of the equations is not shown here. You may read it from the references
given at the end of the chapter. The final result is given as follows:
where J0, J1 und J2 denote Bessel functions of the corresponding order