'Wave' analysis of Venus ionospheric flux ropes

The behavior of the general field fluctuations observed by the Pioneer Venus Orbiter magnetometer in the Venusian ionosphere is approached via the application of wave-analysis techniques to their compressional amplitude, ellipticity, and polarization. The most marked change in these properties occurs within about 15 deg of the terminator; ellipticity and compressional power plummet, implying that flux ropes either drastically change in character there or are confined to the dayside hemisphere, within about 75 percent of the subsolar point. Attention is given to a heuristic model which attempts to unify dayside flux-rope and 'terminator wave' interpretations.