E-Print Archive

There are 4035 abstracts currently viewable.


Advanced Search
Main Page Add New E-Print Submitter
News Help/FAQ About Preferences
Manage Key Phrase
The Global Solar Magnetic Field Through a Full Sunspot Cycle: Observations and Model Results View all abstracts by submitter

Karel Schrijver   Submitted: 2008-06-19 17:16

Based on 11 years of SOHO/MDI observations from the cycle minimum in 1997 to the next minimum around 2008, we compare observed and modeled axial dipole moments to better understand the large-scale transport properties of magnetic flux in the solar photosphere. The absolute value of the axial dipole moment in 2008 is less than half that in the corresponding cycle-minimum phase in early 1997, both as measured from synoptic maps and as computed from an assimilation model based only on magnetogram data equatorward of 60 degrees in latitude. This is incompatible with the statistical fluctuations expected from flux-dispersal modeling developed in earlier work at the level of 7-10 sigma. We show how this decreased axial dipole moment can result from an increased strength of the diverging meridional flow near the Equator, which more effectively separates the two hemispheres for dispersing magnetic flux. Based on the combination of this work with earlier long-term simulations of the solar surface field, we conclude that the flux-transport properties across the solar cycle have changed from preceding cycles to the most recent one. A plausible candidate for such a change is an increase of the gradient of the meridional-flow pattern near the Equator so that the two hemispheres are more effectively separated. The required profile as a function of latitude is consistent with helioseismic and cross-correlation measurements made over past decade.

Authors: C.J. Schrijver and Y. Liu
Projects: SoHO-MDI

Publication Status: Solar Physics, in press.
Last Modified: 2008-09-23 20:59
Go to main E-Print page  New Aspects on Particle Acceleration in Solar Flares from RHESSI Observations  Subject will be restored when possible  Edit Entry  Download Preprint  Submitter's Homepage 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
Why Does the Solar Corona Abnormally Rotate Faster Than the Photosphere?
Impacts On Proton Fluxes Observed During Different Interplanetary Conditions
Coronal Loop Seismology Using Standing Kink Oscillations With a Lookup Table
Data-Optimized Coronal Field Model: I. Proof of Concept
Coronal Bright Points
Difference of source regions between fast and slow coronal mass ejections
Invited Review: Signatures of Magnetic Flux Ropes in the Low Solar Atmosphere Observed in High Resolution
Do Kepler superflare stars really include slowly-rotating Sun-like stars ? - Results using APO 3.5m telescope spectroscopic observations and Gaia-DR2 data -
Magnetically Induced Current Piston for Generating Extreme-ultraviolet Fronts in the Solar Corona
Magnetic Field Dynamics and Varying Plasma Emission in Large-scale Coronal Loops
Nonlinear Evolution of Ion Kinetic Instabilities in the Solar Wind
What determines the X-ray intensity and duration of a solar flare?
Fast Magnetoacoustic Wave Trains with Time-dependent Drivers
Three-dimensional reconstruction of CME-driven shock-streamer interaction from radio observations: a different take on the diagnostics of coronal magnetic fields
The soft X-ray spectrometer polarimeter SolpeX
Variable emission mechanism of a Type IV radio burst
Inference of magnetic field strength and density from damped transverse coronal waves
Frequency-Distance Structure of Solar Radio Sources Observed by LOFAR
The birth of a coronal mass ejection
Properties of slow magnetoacoustic oscillations of solar coronal loops by multi-instrumental observations

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