  A new dynamical parameter, the f-indicator, is introduced and used in order
to distinguish between regular and chaotic motion in galactic Hamiltonian
systems. Two kinds of galactic potentials are used: (i) a global potential,
which describes the whole galaxy and (ii) a local potential, which is made up
of perturbed harmonic oscillators and describes motion near an equilibrium
point. The new indicator is based on the energies of the separable system along
the x, y and z axis. Comparison between the outcomes obtained using the new
dynamical parameter and other methods, such as the maximum Lyapunov
Characteristic Exponent (L.C.E), or the S(c) dynamical spectrum, shows that the
new dynamical indicator gives fast and reliable results concerning the regular
or chaotic character of the orbits. The new indicator was tested in several
Hamiltonian systems of two (2D) degrees and three (3D) degrees of freedom.
