The problem of motions of charged particles or charged grains of matter in
the field of two magnetic dipoles in rotation about a common center are stu
died by means of computing families of periodic solutions and their stabili
ty. Ten such families are found and their stability study shows that only t
wo out of the ten have short arcs of stable members, all with low inclinati
on to the plane of the two dipoles, while the rest of the families consist
exclusively of unstable solutions. Hence the impact of adding one dipole to
the configuration of the Stormer problem, leads to the conclusion that in
the modified system the three-dimensional motions are basically unstable un
like those of the one-dipole case. The model magnetic field used in this st
udy is a first approximation of the Z3 model of the magnetic field of Satur
n as computed from the Pioneer 11 and Voyager 1 and 2 measurements.