The Rate of Emergence of Magnetic Dipoles in Coronal Holes and Adjacent Quiet-Sun Regions

Abstract

Observations from the Michelson Doppler Imager and the EUV Imaging Telescope on the Solar and Heliospheric Observatory are analyzed to determine the rate of emergence of new magnetic flux in coronal holes and in surrounding regions on the quiet Sun. Coronal holes are regions where the open magnetic flux of the Sun, the component that forms the heliospheric magnetic field, is concentrated. It is determined that the rate of emergence of new magnetic flux is systematically lower, by a factor of ~2, in coronal holes relative to the surrounding quiet Sun. This result is consistent with a prediction in a recent model for the transport of open magnetic flux on the Sun, which demonstrated that open flux tends to accumulate and concentrate in regions where the rate of emergence of new magnetic flux is a local minimum.