We apply the MEGNO (Mean Exponential Growth of Nearby Orbits) technique to
the dynamics of Jovian irregular satellites. We demonstrate the efficiency of
applying the MEGNO indicator to generate a mapping of relevant phase-space
regions occupied by observed jovian irregular satellites. The construction of
MEGNO maps of the Jovian phase-space region within its Hill-sphere is addressed
and the obtained results are compared with previous studies regarding the
dynamical stability of irregular satellites. Since this is the first time the
MEGNO technique is applied to study the dynamics of irregular satellites we
provide a review of the MEGNO theory. We consider the elliptic restricted
three-body problem in which Jupiter is orbited by a massless test satellite
subject to solar gravitational perturbations. The equations of motion of the
system are integrated numerically and the MEGNO indicator computed from the
systems variational equations. An unprecedented large set of initial conditions
are studied to generate the MEGNO maps. The chaotic nature of initial
conditions are demonstrated by studying a quasi-periodic orbit and a chaotic
orbit. As a result we establish the existence of several high-order mean-motion
resonances detected for retrograde orbits along with other interesting
dynamical features. The computed MEGNO maps allows to qualitatively
differentiate between chaotic and quasi-periodic regions of the irregular
satellite phase-space given only a relatively short integration time. By
comparing with previous published results we can establish a correlation
between chaotic regions and corresponding regions of orbital instability.Comment: 15 pages, 13 figures, 2 tables, submitted to MNRA