E-Print Archive

There are 4507 abstracts currently viewable.


Advanced Search
Main Page Add New E-Print Submitter
News Help/FAQ About Preferences
Manage Key Phrase
Force-Freeness of Solar Magnetic Fields in the Photosphere View all abstracts by submitter

Yong-Jae Moon   Submitted: 2002-04-05 17:47

It is widely believed that solar magnetic fields are force-free in the solar corona, but not in the solar photosphere at all. In order to examine the force-freeness of active region magnetic fields at the photospheric level, we have calculated the integrated magnetic forces for 12 vector magnetograms of three flare-productive active regions. The magnetic field vectors are derived from simultaneous Stokes profiles of the Fe I doublet 6301.5 and 6302.5 obtained by the Haleakala Stokes Polarimeter of Mees Solar Observatory, with a non-linear least square method adopted for field calibration. The resulting vertical Lorentz force normalized to the total magnetic pressure force |F_z/F_p| ranges from 0.06 to 0.36 with a median value of 0.13, which is smaller than the values (sim 0.4) obtained by Metcalf et al. who applied a weak field derivative method to the Stokes profiles of Na I 5896. Our results indicate that the photospheric magnetic fields are not so far from force-free as conventionally regarded. As a good example of a linear force-free field, AR 5747 is examined. By applying three different methods (a most probable value method, a least square fitting method, and comparison with linear force-free solutions), we have derived relatively consistent linear force-free coefficients for AR 5747. It is found that the scaled downward Lorentz force (|F_z/F_p|) in the solar photosphere decreases with increasing α . Our results also show that the force-freeness of photospheric magnetic fields depends not only on the character of the active region, but also on its evolutionary status.

Authors: Y.-J. Moon, G. S. Choe, H. S. Yun, Y. D. Park, D. L. Mickey

Publication Status: ApJ, 2002, 568, 422-431
Last Modified: 2002-04-05 17:55
Go to main E-Print page  Flaring Time Interval Distribution and Spatial Correlation of Major X-ray Flares  A Revised Shock Time of Arrival (STOA) Model for Interplanetary Shock  Propagation: STOA-2   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
The role and contribution of magnetic fields, characterized via their magnetic flux, to the statistical structuring of the solar atmosphere
Do periods of decayless kink oscillations of solar coronal loops depend on noise?
Automatic detection technique for solar filament oscillations in GONG data
Probing the Density Fine Structuring of the Solar Corona with Comet Lovejoy
Confined plasma transition from the solar atmosphere to the interplanetary medium
Extracting the Heliographic Coordinates of Coronal Rays using Images from WISPR/Parker Solar Probe
Two-spacecraft detection of short-period decayless kink oscillations of solar coronal loops
Genesis and Coronal-jet-generating Eruption of a Solar Minifilament Captured by IRIS Slit-raster Spectra
First detection of transverse vertical oscillation during the expansion of coronal loops
A New Position Calibration Method for MUSER Images
Sigmoid Formation Through Slippage of A Single J-shaped Coronal Loop
MHD Simulation of Homologous Eruptions from Solar Active Region 10930 Caused by Sunspot Rotation
Dropouts of Fully Stripped Ions in the Solar Wind: A Diagnostic for Wave Heating versus Reconnection
Plasma heating and nanoflare caused by slow-mode wave in a coronal loop
The Lyman-α Emission in a C1.4 Solar Flare Observed by the Extreme Ultraviolet Imager aboard Solar Orbiter
Imaging and Spectroscopic Observations of the Dynamic Processes in Limb Solar Flares
Evolution of the critical torus instability height and CME likelihood in solar active regions
A Magnetogram-matching Method for Energizing Magnetic Flux Ropes Toward Eruption
A 2D Model for Coronal Bright Points: Association with Spicules, UV bursts, Surges and EUV Coronal Jets
The relativistic solar particle event on 28 October 2021: Evidence of particle acceleration within and escape from the solar corona

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

© 2000-2020 Solar Physics Group - Montana State University