Measurements of fluctuations in total electron content made with a radio interferometer reveal weak but frequency outbursts of total-electron-content disturbances, with trace azimuths roughly westward, with trace speeds up to ~2 km/s, and with temporal periods in the range 100--500 seconds. Statistical tests of the dataset suggest that these disturbances are due to drift of plasmaspheric irregularities past the radio lines-of-sight. The phenomenon is likely to provide a new passive tracer of zonal convection in the inner magnetosphere. ¿ American Geophysical Union 1995.