E-Print Archive

There are 4089 abstracts currently viewable.


Advanced Search
Main Page Add New E-Print Submitter
News Help/FAQ About Preferences
Manage Key Phrase
Subject will be restored when possible View all abstracts by submitter

Na Deng   Submitted: 2007-09-23 21:17

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.

Authors: Na Deng, Debi Prasad Choudhary, Alexandra Tritschler, Carsten Denker, Chang Liu, Haimin Wang
Projects: None

Publication Status: The Astrophysical Journal, accepted September, 2007
Last Modified: 2007-09-24 04:01
Go to main E-Print page  Subject will be restored when possible  Subject will be restored when possible  Edit Entry  Download Preprint  Delete Entry 

Go to main E-Print pageGo to main E-Print page.
Previous AbstractPrevious Abstract.
Next AbstractNext Abstract.
Download PreprintDownload Preprint.
Submitter's HomepageSubmitters Homepage.
Edit EntryEdit Entry.
View All Abstracts By SubmitterView all abstracts by submitter.
Delete AbstractDelete abstract.

Latest Entries
Fundamental Transverse Vibrations of the Active Region Solar Corona
Damping of slow magnetoacoustic oscillations by the misbalance between heating and cooling processes in the solar corona
Magnetic helicity and eruptivity in active region 12673
Impulsive coronal heating from large-scale magnetic rearrangements: from IRIS to SDO/AIA
Probing the effect of cadence on the estimates of photospheric energy and helicity injections in eruptive active region NOAA AR 11158
The birth of a coronal mass ejection
Oscillations of the baseline of solar magnetic field and solar irradiance on a millennial timescale
Chromospheric cannonballs on the Sun
Magnetic Helicity from Multipolar Regions on the Solar Surface
Exoplanet predictions based on harmonic orbit resonances
The width distribution of solar coronal loops and strands - Are we hitting rock bottom ?
Order out of randomness: Self-organization processes in astrophysics
Convection-driven generation of ubiquitous coronal waves
The minimum energy principle applied to Parker's coronal braiding and nanoflaring scenario
Self-organizing systems in planetary physics: Harmonic resonances of planet and moon orbits
Global energetics of solar flares: VIII. The Low-Energy Cutoff
Global energetics of solar flares: VIII. The Low-Energy Cutoff
Global Energetics of Solar Flares: VII. Aerodynamic Drag in Coronal Mass Ejections
Self-organized criticality in solar and stellar flares: Are extreme events scale-free ?
A Wavelet Based Approach to Solar-Terrestrial Coupling

Related Pages
MSU Solar Physics.
Max Millennium Science Mail Archive.
Max Millennium Message of the Day Mail Archive.
Max Millennium Flare Catalog

Archive Maintainer
Alisdair Davey

© 2003 Solar Physics Group - Montana State University