  We consider the problem of electromagnetic geodesics, all of whose energy are
the same, bifurcating from a given one. By considering a local variational
principle which keeps fixed the energy we obtain the adequate notion of
conjugacy along an electromagnetic geodesic. Then we employ a functional
analytic criterion for bifurcation of critical points of strongly indefinite
functionals, based on the so-called crossing form, to obtain a sufficient
condition for bifurcation of electromagnetic geodesics to occur.
