Magnetic Flux Loss and Flux Transport in a Decaying Active Region

Abstract

We estimate the temporal change of magnetic flux perpendicular to the solar surface in a decaying active region by using a time series of the spatial distribution of vector magnetic fields in the photosphere. The vector magnetic fields are derived from full spectropolarimetric measurements with the Solar Optical Telescope aboard Hinode. We compare a magnetic flux loss rate to a flux transport rate in a decaying sunspot and its surrounding moat region. The amount of magnetic flux that decreases in the sunspot and moat region is very similar to magnetic flux transported to the outer boundary of the moat region. The flux loss rates [$(dF/dt{)}_{loss}$] of magnetic elements with positive and negative polarities are balanced each other around the outer boundary of the moat region. These results suggest that most of the magnetic flux in the sunspot is transported to the outer boundary of the moat region as moving magnetic features, and then removed from the photosphere by flux cancellation around the outer boundary of the moat region.

16 pages, 7 figures, Accepted for publication in ApJ

References in corpus (3)

• The Solar Optical Telescope for the Hinode Mission: An Overview
• Disintegration of Magnetic Flux in Decaying Sunspots as Observed with the Hinode SOT
• Discovery of inward moving magnetic enhancements in sunspot penumbrae

Cited by in corpus (8)

• Magnetic Properties and Flow Angle of the Inverse Evershed Flow at Its Downflow Points
• Investigation of the Middle Corona with SWAP and a Data-Driven Non-Potential Coronal Magnetic Field Model
• Evolution of the Magnetic Field Distribution of Active Regions
• The Decay of Two Adjacent Sunspots Associated with Moving Magnetic Features
• The role of the Lorentz force in sunspot equilibrium
• Temporal Variation of Flare Occurrence Rates via the Spot Evolution on the Sun and Solar-type Stars
• Statistical analysis of the total magnetic flux decay rate in solar active regions
• Estimation of the lifetime of slow-decaying unipolar active regions in the framework of the turbulent erosion model