  The topic of this article is the numerical search of codimension 2 Normally
Hyperbolic Invariant Manifolds (NHIM) in Hamiltonian systems with 3 degrees of
freedom and their internal dynamics. We point out relations between different
strategies to find such surfaces numerically. We can start from index-1 saddles
of the effective potential or from a partially integrable case and follow the
NHIM along some curve in the parameter space of the system. Or, we can look for
the stable and unstable manifolds of such surfaces by an appropriate indicator
method. We show numerical examples for an electron moving in a perturbed
magnetic dipole field.
