E-Print Archive

There are 3950 abstracts currently viewable.


Advanced Search
Main Page Add New E-Print Submitter
News Help/FAQ About Preferences
Manage Key Phrase
Recent theoretical and observational developments in magnetic helicity studies View all abstracts by submitter

Pascal Demoulin   Submitted: 2006-12-15 09:29

Magnetic helicity quantifies how the magnetic field is sheared and twisted compared to its lowest energy state (potential field). Such stressed magnetic fields are usually observed in association with flares, eruptive filaments, and coronal mass ejections (CMEs). Magnetic helicity plays a key role in magnetohydrodynamics because it is almost preserved on a timescale less than the global diffusion time scale. Its conservation defines a constraint to the magnetic field evolution. Only relatively recently, scientists have realized that magnetic helicity can be computed from observations, and methods have been derived to bridge the gap between theory and observations. At the photospheric level, the rate (or flux) of magnetic helicity can be computed from the evolution of longitudinal magnetograms. The coronal helicity is estimated from magnetic extrapolation, while the helicity ejected in magnetic clouds (interplanetary counter-part of CMEs) is derived through modelling of in-situ magnetic field measurements. Using its conserved property, a quantitative link between phenomena observed in the corona and then in the interplanetary medium has been achieved.

Authors: Démoulin, Pascal
Projects: SoHO-MDI

Publication Status: Advances in Space Research, in press
Last Modified: 2006-12-15 10:37
Go to main E-Print page  Stereoscopy basics for the STEREO mission  Coronal prominence structure and dynamics: A magnetic flux rope interpretation  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
Frequency rising sub-THz emission from solar flare ribbons
Particle acceleration in coalescent and squashed magnetic islands I. Test particle approach
Statistical Analysis of Torus and Kink Instabilities in Solar Eruptions
Solar Eruptions, Forbush Decreases and Geomagnetic Disturbances from Outstanding Active Region 12673
Coronal hard X-ray sources revisited
Manifestations of bright points observed in G-band and Ca II H by Hinode/SOT
Propagation of Leaky MHD Waves at Discontinuities with Tilted Magnetic Field
Time variations of the non-potential and volume-threading magnetic helicities
Advances in mean-field dynamo theory and applications to astrophysical turbulence
Reverse Current Model for Coronal Mass Ejection Cavity Formation
Predictions of DKIST/DL-NIRSP Observations for an Off-limb Kink-unstable Coronal Loop
Exploring the biases of a new method based on minimum variance for interplanetary magnetic clouds
The non-modal onset of the tearing instability
SpatioTemporal Evolution and North-South Asymmetry of Quasi-Biennial Oscillations in the Coronal Fe XIV Emission
Corotating Shock Waves and the Solar-Wind Source of Energetic Ion Abundances: Power Laws in A/Q
Coronal condensations caused by magnetic reconnection between solar coronal loops
Measurement of Vector Magnetic Field in a Flare kernel with a Spectropolarimetric Observation in He I 10830 A
The Relation Between Escape and Scattering Times of Energetic Particles in a Turbulent Magnetized Plasma: Application to Solar Flares
Implications of loop-top origin for microwave, hard X-ray, and low-energy gamma-ray emissions from behind the limb flares
Solar radio emission as a disturbance of aeronautical radionavigation

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