E-Print Archive

There are 4507 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
Current sheet formation in quasi-separatrix layers and hyperbolic flux tubes View all abstracts by submitter

Guillaume Aulanier   Submitted: 2005-07-22 07:49

In 3D magnetic field configurations, quasi-separatrix layers (QSLs) are defined as volumes in which field lines locally display strong gradients of connectivity. Considering QSLs as the preferential locations for current sheet development and magnetic reconnection in general, and as a natural model for solar flares and coronal heating in particular, have been strongly debated issues over the last decade. In this paper, we perform zero-eta resistive MHD simulations of the development of electric currents in smooth magnetic configurations, which are strictly speaking bipolar though they are formed by four flux concentrations, and whose potential fields contain QSLs. The configurations are driven by smooth and large-scale sub-Alfvénic footpoint motions. Extended electric currents naturally form in the configurations, which evolve through a sequence of quasi non-linear force-free equilibria. Narrow current layers also develop. They spontaneously form at small scales, all around the QSLs, whatever the footpoint motions are. For long enough motions, the strongest currents develop where the QSLs are the thinnest, namely at the Hyperbolic Flux Tube (HFT) which generalizes the concept of separator. These currents progressively take the shape of an elongated sheet, whose formation is associated with a gradual steepening of the magnetic field gradients over tens of Alfvén times, due to the different motions applied to the field lines which pass on each side of the HFT. Our model then self-consistently accounts for the long-duration energy storage prior to a flare, followed by a switch-on of reconnection when the currents reach the dissipative scale at the HFT. In configurations whose potential fields contain broader QSLs, when the magnetic field gradients reach the dissipative scale, the currents at the HFT %quasi-separator reach higher magnitudes. This implies that major solar flares, that are not related with an early large-scale ideal instabilities, must occur in regions whose corresponding potential fields have broader QSLs. Our results lead us to conjecture that physically, current layers must always form on the scale of the QSLs. This implies that electric currents around QSLs may be gradually amplified in time only if the QSLs are broader than the dissipative length-scale. We also discuss the potential role of QSLs in coronal heating in bipolar configurations made of a continuous distribution of flux concentrations.

Authors: G. Aulanier, E. Pariat and P. Demoulin
Projects: None

Publication Status: A&A (accepted)
Last Modified: 2005-07-22 07:49
Go to main E-Print page  Toward Interplanetary Space Weather: Strategies for Manned Missions to Mars  The Localization of Particle Acceleration Sites in Solar Flares and CMEs  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 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