We discuss our modeling that is aimed to reproduce the observed dust impact rates during the first two Ganymede encounters of Galileo. We use a detailed fields and particles model of the magnetosphere and simultaneously follow the dynamics and the charging history of small dust particles. We assume Io to be the only source of the escaping dust grains and show that our model matches the gross characteristics of the observations. We argue that the large scale dawn-to-dusk electric field can be responsible for shaping the emission pattern of dust from the Io plasma torus. The emission pattern shows a minimum flux toward the Sun, perhaps explaining why the observed fluxes did not increase as Galileo approached the source region of the dust particles. We show that the general shape of the trajectories of the grains offers a good explanation for the sudden shift in the observed direction of the dust impacts. Modeling the observed dust impact rates gives an excellent opportunity to test our particles and fields model of Jupiter's magnetosphere.¿ 1997 American Geophysical Union