An estimate of the spread of trajectories for Kahler magnetic fields

On a Kahler manifold we consider trajectories under the influence of Kahler magnetic fields. They are smooth curves which are parameterized by their arclengths and whose velocities and normal vectors form complex lines. In this paper we study how trajectories spread, and give an estimate of norms of magnetic Jacobi fields from below and an estimate of area elements of trajectory-spheres.