Bob Leighton, examining the spectroheliograph during a visit to Kitt Peak in 1968. His guide, the author, is on the right.
Ducks enjoying a tour of Boston. Even though the current is faster on one side of the Charles than the other, the ducks form a stationary pattern because they are paddling toward the Boston shore. From Wang (1998).
Time/latitude plots of the axisymmetric component of the simulated photospheric magnetic field during sunspot cycle 21. When the sources are not accompanied by a latitudinal component of transport, wide polarity bands are formed, with the leading polarity dominating near the equator and the trailing polarity dominating at higher latitudes (top panel). When the sources are accompanied by a 600 km2 s–1 diffusion, the equatorial bands of flux are annihilated and the high-latitude bands spread out smoothly to produce the broad latitudinal distribution of a dipole field (middle panel). When the sources are accompanied by diffusion and a steady 10 m s–1 poleward flow, they create several poleward surges of flux and a highly concentrated polar field (bottom panel).
Longitude/latitude plots of the field consisting of an axisymmetric dipole and an idealized bipolar magnetic region at the equator. The bipolar region distorts the polar-hole boundaries into spurs that are relatively unaffected by differential rotation. Because the bipolar region and the coronal-hole deformations rotate with the 26.9-day equatorial period, they drift very slightly in the 27.27-day Carrington frame used for the maps.
© Max Planck Society and the author(s)