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Helicity Computation

Description

  • Inputs: The images containing identified hot and cold loops and tables describing the loop time and endpoint locations from LoopRecognition will be input along with the magnetic field line images and time / location information from MagneticFieldExtrapolation.

  • Outputs: HelicityComputation will output a number representing the helicity (or proportion of free energy) associated with an active region. Helicity can be sampled at a 30 minute cadence (or whatever frequency is deemed most useful / appropriate by SDO scientists).

Literature Search

Algorithms:

Title
Observations of Magnetic Helicity
Author(s)
L.van Driel-Gesztelyi, P.Demoulin, C.H.Mandrini
Publication
Advances in Space Research, Volume 32, Issue 10, p. 1855-1866
URL
http://www.solaire.obspm.fr/demoulin/03/review_H_cospar.pdf
Date published
2003
Description
Overview of the observational studies into the two major sources of Solar Magnetic Helicity: Photospheric Plasma Motions and emergent Twisting Flux Tubes

Title
Global budget for an eruptive active region
Author(s)
A.Bleybel, T.Amari, L.van Driel-Gesztelyi and K.D.Leka
Publication
Astronomy & Astrophysics, Volume 395, p. 685-695
URL
http://www.edpsciences.org/articles/aa/pdf/2002/44/aa2125.pdf
Date published
2002
Description
Results of observations of the magnetic structure of NOAA Active Region #7912 in October 1995. This paper is of interest because it describes the use of a nonlinear force-free magnetic field model to compute the magnetic helicity of the active region.

Title
3D magnetic configuration of the H-alpha filament and X-ray sigmoid in NOAA AR 8151
Author(s)
S.Regnier and T.Amari
Publication
Astronomy & Astrophysics 425, p.345-352
URL
http://www.edpsciences.org/articles/aa/pdf/2004/37/aa0383-03.pdf
Date published
June, 2004
Description
Describes the use of the Grad-Rubin nlff technique to reconstruct the magnetic field of active region NOAA AR 8151 from a vector magnetogram and use this to identify flux systems.

Title
Self and mutual magnetic helicities in coronal magnetic configurations
Author(s)
S.Regnier, T.Amari and R.C.Canfield
Publication
Astronomy & Astrophysics 442, p.345-349
URL
http://www.edpsciences.org/articles/aa/pdf/2005/40/aa3509-05.pdf
Date published
July 2005
Description
Describes a new technique to evaluate various components of the total magnetic helicity in the corona for an equilibrium magnetic field reconstructed using the Grad-Rubin nlff technique. Subject of a talk given by S.Regnier at MSSL, 25th May 2006

Title
Dynamical Formation and Stability of Helical Prominence Magnetic Fields
Author(s)
C.Richard DeVore and Spiro K. Antiochos
Publication
The Astrophysical Journal 539:954-963
URL
http://www.journals.uchicago.edu/ApJ/journal/issues/ApJ/v539n2/51179/51179.web.pdf
Date published
20th August 2000
Description
Describes the effects of shear motion near and parallel to the photospheric polarity inversion line of a bipolar magnetic field. The shear motion is simulated using the MHD simulation package FCTMHD3D, devised by Dr DeVore.

Additional Papers

  1. De Moortel, I., 2005, Phil Trans R. Soc A, Vol 363, 2743 - 2760 (full paper)
  2. DeVore, C, 2000, ApJ, 539, 944 - 953 (full paper)

Routines and Libraries

Test Data

Comments

-- MikeSmith - 26 Jan 2007

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Topic revision: r8 - 2007-01-26 - MikeSmith
 
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