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
A Model for the Origin of High Density in Loop-top X-ray Sources View all abstracts by submitter

Dana Longcope   Submitted: 2011-07-14 10:58

Super-hot looptop sources, detected in some large solar flares, are compactsources of HXR emission with spectra matching thermal electron populationsexceeding 30 megakelvins. High observed emission measure, as well as inferenceof electron thermalization within the small source region, both provideevidence of high densities at the looptop; typically more than an order ofmagnitude above ambient. Where some investigators have suggested such densityenhancement results from a rapid enhancement in the magnetic field strength, wepropose an alternative model, based on Petschek reconnection, whereby looptopplasma is heated and compressed by slow magnetosonic shocks generatedself-consistently through flux retraction following reconnection. Under steadyconditions such shocks can enhance density by no more than a factor of four.These steady shock relations (Rankine-Hugoniot relations) turn out to beinapplicable to Petschek's model owing to transient effects of thermalconduction. The actual density enhancement can in fact exceed a factor of tenover the entire reconnection outflow. An ensemble of flux tubes retractingfollowing reconnection at an ensemble of distinct sites will have a collectiveemission measure proportional to the rate of flux tube production. This rate,distinct from the local reconnection rate within a single tube, can be measuredseparately through flare ribbon motion. Typical flux transfer rates and loopparameters yield emission measures comparable to those observed in super-hotsources.

Authors: D.W. Longcope, S.E. Guidoni
Projects: None

Publication Status: ApJ (accepted)
Last Modified: 2011-07-14 15:24
Go to main E-Print page  Magnetic Energy Storage and Current Density Distributions for Different Force-Free Models  Anatomy of a solar flare: measurements of the December 14, 2006 X-class flare with GONG, Hinode and RHESSI  Edit Entry  Download Preprint  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