Approximately 2500 equatorward boundaries of auroral electron precipitation were determined for times when hourly averages of the interplanetary magnetic field and solar wind velocity V were available. The equatorward boundaries were determined from data returned by the SSJ/3 electron detector on board the DMSP/F2 satellite in magnetic local sectors between 0400 and 1100 hours on the morningside of the oval and between 1500 and 2300 hours on the eveningside of the oval. The boundary data were separated into 1-hour zones in magnetic local time. Within each zone the boundary locations were studied as functions of Bz and Bz2, VBz and VBz2. Significant results were obtained when the boundaries were correlated with hourly average of Bz and VBz for the hour preceding the one in which the boundary was measured and when the linear regression was performed separately for data points where Bz?1 nT and Bz>1 nT. For points where Bz1 nT, the correlation with Bz and VBz gave slopes generally between 0.8¿ and 1.2¿/nT and between 1.5¿ and 2.5¿/mV/m, respectively, with correlation coefficients of ~0.7. The latitudes of the intercepts tend to decrease with increasing local time in the evening sector and with decreasing local time in the morning sector. In the range above 1 nT, the slope of the best fit line for correlation with Bz, and VBz changes sign. Slopes fall in the range -0.1¿ to -0.4¿/nT and 0.21¿ to 1¿/mV/m. Correlation coefficients are typically worse than -0.4. Correlations of the boundary with Bz2 and VBz2 for both ranges of Bz are uniformly worse than those for Bz and VBz. The trend in slopes and intercepts with magnetic local time for Bz?1 nT is found to be similar to that previously found for the correlation of the boundaries with Kp (Gussenhoven et al, 1981). In this range of Bz, KP, VB, are found to be related by the equation Kp = 2.01- 0.91 VBz (mV/m). From the work of Ejiri et al. (1978) an equation relating the magnetospheric electric potential to VBz is derived. The results are in agreement with the general features of the half-wave rectifier model of the magnetosphere and measurements of polar cap potential.