Data from the Voyager plasma science instrument is used to set limits on transport models for the inner Jovian magnetosphere. The instrument has an effective time resolution for detecting changes in density of 0.24 s, which corresponds to a spatial resolution of about 20 km (equal to the gyroradius of an oxygen ion) in the region just outside of Io. This resolution enables us to put an upper limit of about 10% on changes in density between adjacent magnetic flux tubes, which rules out transport models which invoke inward motion of near empty flux tubes to replace outward-moving flux tubes carrying Iogenic plasma. ¿ American Geophysical Union 1987