Showing papers by "J. Todd Hoeksema published in 2009"

Evolution of the large-scale magnetic field over three solar cycles

Abstract: Observations of the large-scale magnetic field show that the current extended solar cycle minimum is different from the three previous well-observed minima. The weaker polar fields increase the relative influence of middle and low-latitude flux patterns on the configuration of the corona and heliosphere. A much larger portion of the open flux originates in equatorial coronal holes. Even though the mean magnetic field of the Sun as a star is the weakest since measurements began, the sector structure of the interplanetary field, though smaller in magnitude, reached fairly high latitude until 2009. The emergence of active regions through the cycle and transport of flux from low to high latitudes also show quite different patterns, providing insight into the dynamo that drives the cycle. Long records of synoptic observations provide a rich source of information about solar activity that must be maintained.