Bipolar Magnetic Fields Emerging at High Latitudes

Three examples of the unusual development of high-latitude large-scale features during cycle 23 are described. These features are found in synoptic plots constructed using data obtained at both the NSOKP and the MWO Observatories. Several properties of these features cannot be reproduced in direct simulations using a modified form of the flux-transport equation appropriate for synoptic fields and it is inferred that their evolution is not due solely to the advection and diffusion of decaying active region fields. The analysis shows that one feature may be related to a high-latitude bipolar region which emerged in an earlier rotation. By imposing the locations of H filaments on enlargements of the NSOKP daily magnetograms, we can identify the location of the other features and study their structure at high resolution. This suggests that they are related to the emergence of small magnetic knots at high latitudes. By repeating the simulations including overlays of non-random patterns of bipoles emerging at appropriate times during the simulations, it is possible to study the effects of different patterns and to reproduce some of the qualitative properties of these features not present in the direct simulations. These results support Stenflo's contention that `quite minute deviations from a random distribution (in the emergence of small-scale fields) would suffice for these fields to have global effects'.