Comparisons of electron and proton distribution functions are made with dc electric field measurements as the S3-3 satellite crossed a series of high-latitude acceleration regions near local dusk on July 29, 1976. Potential drops, from parallel electric fields, are inferred from charged particle distributions using adiabatic theory and compared with potentials calculated from measured perpendicular electric fields. There exists a one to one spatial relationship between strong dc electric field enhancements in the form of electric field reversals and acceleration signatures of auroral particles. From the charged particle and electric field analysis, we conclude that electric fields, parallel to B, caN extend above and below the satellite altitude near 7500 km when strong electrostatic field reversals are encountered. Within the uncertainties of our analysis, the potential drop below the satellite is comparable to the potential calculated from the individual electrostatic structures crossed by the satellite. There are, in addition, particle signatures that imply a source of strong acceleration was located above and relatively close to the satellite. These accelerated electrons are coincident with auroral hiss and ion conics. In addition to regions of acceleration that extended only fractions of a degree in latitude, there was a broad 'inverted V structure' near the polar cap boundary where strong perpendicular electric fields ere embedded, giving rise to large variations in the inferred potential below the satellite.