E-Print Archive

There are 4371 abstracts currently viewable.


Search:

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

Guillaume Aulanier   Submitted: 2007-09-26 02:32

EIT waves are observed in EUV as bright fronts. Some of these bright fronts propagate across the solar disc. EIT waves are all associated with a flare and a CME and flare commonly interpreted as fast-mode magnetosonic waves. Propagating EIT waves could also be the direct signature of the gradual opening of magnetic field lines during a CME. We quantitatively addressed this alternative interpretation. Using two independent 3D MHD codes, we performed non-dimensional numerical simulations of a slowly rotating magnetic bipole, which progressively result in the formation of a twisted magnetic flux tube and its fast expansion, as during a CME. We analyse the origins, the development and the observability in EUV of narrow electric currents sheets which appear in the simulations. Both codes give similar results which we confront with two well-known SoHO/EIT observations of propagating EIT waves (April 7 and May 12, 1997), by scaling the vertical magnetic field components of the simulated bipole to the line of sight magnetic field observed by SoHO/MDI and the sign of helicity to the orientation of the soft X-ray sigmoids observed by Yohkoh/SXT. A large-scale and narrow current shell appears around the twisted flux tube in the dynamic phase of its expansion. This current shell is formed by the return currents of the system, which separate the twisted flux tube from the surrounding fields. It intensities as the flux tube accelerates and it is co-spatial with weak plasma compression. The current density integrated over the altitude has a shape of an ellipse which expands and rotates when viewed from above, reproducing the generic properties of propagating EIT waves. The timing, orientation and location of bright and faint patches observed in the two EIT waves are remarkably well reproduced. We conjecture that propagating EIT waves are the observational signature of Joule heating in electric current shells, which separate expanding flux tubes from their surrounding fields during CMEs or plasma compression inside this current shell. We also conjecture that the bright edges of halo CMEs show the plasma compression in these current shells.

Authors: C. Delannee, T. Torok, G. Aulanier, J.-F. Hochedez
Projects: SoHO-EIT,SoHO-MDI,SoHO-LASCO,Yohkoh-SXT

Publication Status: Solar Physics (published)
Last Modified: 2008-02-15 00:59
Go to main E-Print page  Subject will be restored when possible  Subject will be restored when possible  Edit Entry  Download Preprint  Submitter's Homepage Delete Entry 

Key
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 Poissonian origin of power laws in solar flare waiting time distributions
Correlation of the sunspot number and the waiting time distribution of solar flares, coronal mass ejections, and solar wind switchback events observed with the Parker Solar Probe
Self-organized criticality in stellar flares
Finite system-size effectrs in self-organizing criticality systems
Global energetics of solar flares. XII. Energy scaling laws
Global energetics of solar flares. XI. Flare magnitude predictions of the GOES class
Are the Magnetic Fields Radial in the Solar Polar Region?
Fast magnetoacoustic wave trains: from tadpoles to boomerangs
Multi-channel coronal hole detection with convolutional neural networks
FOXSI-2 Solar Microflares. II. Hard X-ray Imaging Spectroscopy and Flare Energetics
Structure and Evolution of an Inter–Active Region Large-scale Magnetic Flux Rope
Variation of Magnetic Flux Ropes through Major Solar Flares
MHD Modeling of Solar Coronal Magnetic Evolution Driven by Photospheric Flow
The Causes of Peripheral Coronal Loop Contraction and Disappearance Revealed in a Magnetohydrodynamic Simulation of Solar Eruption
The Sun's Dynamic Extended Corona Observed in Extreme Ultraviolet
Magnetohydrodynamic Simulations of Spicular Jet Propagation Applied to Lower Solar Atmosphere Model
Thermal Trigger for Solar Flares II: Effect of the Guide Magnetic Field
The role of non-axisymmetry of magnetic flux rope in constraining solar eruptions
Energy budget of plasma motions, heating, and electron acceleration in a three-loop solar flare
Space weather: the solar perspective - an update to Schwenn (2006)

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