  We describe a method for symplectic tracking of charged particles through
static electric and magnetic fields. The method can be applied to cases where
the fields have a dependence on longitudinal as well as transverse position,
and where the reference trajectory may have non-zero curvature. Application of
the method requires analytical expressions for the scalar and vector
potentials: we show how suitable expressions, in the form of series analogous
to multipole expansions, can be constructed from numerical field data, allowing
the method to be used in cases where only numerical field data are available.

Accelerator Physics