Using the methods of multi- and partial-linear-correlation, we demonstrate that both the solar wind density and the solar wind electric field make significant and independent contributions to the strength of the ring current, as measured by the Dst* index, during mild storms. The solar wind data were obtained from WIND, and the Dst data from OmniWeb. After appropriate cleaning of the data, 55 events from the Wind-era with Dst* excursions below -50 were obtained. Correlations with Dst* were performed with independent, variable time lags for the density and for the electric field, and the optimal time lags are found to be approximately 5 hours for density and less than one hour for the electric field (in addition to the time shift to Earth). ¿ 1999 American Geophysical Union