Flow Field Evolution of a Decaying Sunspot

Details Flow Field Evolution of a Decaying Sunspot Flow Field Evolution of a Decaying Sunspot

2007-09-21

arxiv.org/abs/0709.3340v1

Astronomy and Astrophysics

Astrophysics

9 pages, 7 figures, The Astrophysical Journal, accepted September, 2007

Scientific paper

10.1086/523102

We study the evolution of the flows and horizontal proper motions in and around a decaying follower sunspot based on time sequences of two-dimensional spectroscopic observations in the visible and white light imaging data obtained over six days from June~7 to~12, 2005. During this time period the sunspot decayed gradually to a pore. The spectroscopic observations were obtained with the Fabry-P\'{e}rot based Visible-Light Imaging Magnetograph (VIM) in conjunction with the high-order adaptive optics (AO) system operated at the 65 cm vacuum reflector of the Big Bear Solar Observatory (BBSO). We apply local correlation tracking (LCT) to the speckle reconstructed time sequences of white-light images around 600 nm to infer horizontal proper motions while the Doppler shifts of the scanned \FeI line at 630.15 nm are used to calculate line-of-sight (LOS) velocities with sub-arcsecond resolution. We find that the dividing line between radial inward and outward proper motions in the inner and outer penumbra, respectively, survives the decay phase. In particular the moat flow is still detectable after the penumbra disappeared. Based on our observations three major processes removed flux from the sunspot: (a) fragmentation of the umbra, (b) flux cancelation of moving magnetic features (MMFs; of the same polarity as the sunspot) that encounter the leading opposite polarity network and plages areas, and (c) flux transport by MMFs (of the same polarity as the sunspot) to the surrounding network and plage regions that have the same polarity as the sunspot.

Affiliated with

Also associated with

No associations

Rating

Flow Field Evolution of a Decaying Sunspot does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Flow Field Evolution of a Decaying Sunspot, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Flow Field Evolution of a Decaying Sunspot will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-256238