E-Print Archive

There are 4002 abstracts currently viewable.


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

Lyndsay Fletcher   Submitted: 2008-02-12 04:59

The impulsive phase of a solar flare marks the epoch of rapid conversion of energy stored in the pre-flare coronal magnetic field. Hard X-ray observations imply that a substantial fraction of flare energy released during the impulsive phase is converted to the kinetic energy of mildly relativistic electrons (10-100 keV). The liberation of the magnetic free energy can occur as the coronal magnetic field reconfigures and relaxes following reconnection. We investigate a scenario in which products of the reconfiguration - large-scale Alfvén wave pulses - transport the energy and magnetic-field changes rapidly through the corona to the lower atmosphere. This offers two possibilities for electron acceleration. Firstly, in a coronal plasma with beta < m_e/m_p, the waves propagate as inertial Alfvén waves. In the presence of strong spatial gradients, these generate field-aligned electric fields that can accelerate electrons to energies on the order of 10 keV and above, including by repeated interactions between electrons and wavefronts. Secondly, when they reflect and mode-convert in the chromosphere, a cascade to high wavenumbers may develop. This will also accelerate electrons by turbulence, in a medium with a locally high electron number density. This concept, which bridges MHD-based and particle-based views of a flare, provides an interpretation of the recently-observed rapid variations of the line-of-sight component of the photospheric magnetic field across the flare impulsive phase, and offers solutions to some perplexing flare problems, such as the flare ''number problem'' of finding and resupplying sufficient electrons to explain the impulsive-phase hard X-ray emission.

Authors: Fletcher, L., Hudson, H. S.
Projects: None

Publication Status: ApJ (in press)
Last Modified: 2008-02-12 11:09
Go to main E-Print page  Subject will be restored when possible  Subject will be restored when possible  Edit Entry  Download Preprint  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
The Role of a Tiny Brightening in a Huge Geo-effective Solar Eruption Leading to the St Patrick's Day Storm
A basal contribution from p-modes to the Alfvénic wave flux in the corona
Multiwavelength Study of Equatorial Coronal-Hole Jets
Non-thermal hydrogen Lyman line and continuum emission in solar flares generated by electron beams
Determining normal mode features from numerical simulations using CEOF analysis: I. Test case using transverse oscillations of a magnetic slab
Modelling the Effect of Mass-Draining on Prominence Eruptions
Transverse waves in coronal flux tubes with thick boundaries: The effect of longitudinal flows
Electron distribution and energy release in magnetic reconnection outflow regions during the pre-impulsive phase of a solar flare
Benchmarking CME arrival time and impact: Progress on metadata, metrics, and events
First Unambiguous Imaging of Large-Scale Quasi-Periodic Extreme-Ultraviolet Wave or Shock
Coronal Imaging with the Solar UltraViolet Imager
Investigation of pre-flare dynamics using the weighted horizontal magnetic gradient method: From small to major flare classes
Seismological determination of the Alfvén speed and plasma-beta in solar photospheric bright points
Dynamo Wave Patterns Inside the Sun Revealed by Torsional Oscillations
Evidence of Twisting and Mixed-polarity Solar Photospheric Magnetic Field in Large Penumbral Jets: IRIS and Hinode Observations
Dissipation scale lengths of density turbulence in the inner solar wind
On the Possibility of Generating Harmonics of the Electron Plasma Frequency in the Solar Atmosphere due to Explosive Instability in a System of Interpenetrating Electron and Ion Flows
Determination of the total accelerated electron rate and power using solar flare hard X-ray spectra
Transition from axi- to nonaxisymmetric dynamo modes in spherical convection models of solar-like stars
Can high-mode magnetohydrodynamic waves propagating in a spinning macrospicule be unstable due to the Kelvin-Helmholtz instability?

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