E-Print Archive

There are 4080 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
Low-Energy Cutoffs in Electron Spectra of Solar Flares: Statistical Survey View all abstracts by submitter

Eduard Kontar   Submitted: 2008-07-02 03:22

The Ramaty High Energy Solar Spectroscopic Imager (RHESSI) X-ray data base (February 2002 - May 2006) has been searched to find solar flares with weak thermal components and flat photon spectra. Using a regularised inversion technique, we determine the mean electron flux distribution from count spectra for a selection of events with flat photon spectra in the 15-20 keV energy range. Such spectral behaviour is expected for photon spectra either affected by photospheric albedo or produced by electron spectra with an absence of electrons in a given energy range, e.g. a low-energy cutoff in the mean electron spectra of non-themal particles. We have found 18 cases which exhibit a statistically significant local minimum (a dip) in the range of 13-19 keV. The positions and spectral indices of events with low-energy cutoff indicate that such features are likely to be the result of photospheric albedo. It is shown that if the isotropic albedo correction is applied, all low-energy cutoffs in the mean electron spectrum are removed and hence the low energy cutoffs in the mean electron spectrum of solar flares above sim12 keV cannot be viewed as real features. If low-energy cutoffs exist in the mean electron spectra, their energies should be less than sim12 keV.

Authors: Kontar, E.P., Dickson, E., Kasparova, J.
Projects: RHESSI

Publication Status: submitted to Solar Physics
Last Modified: 2008-09-23 20:57
Go to main E-Print page  The cyclic behavior of solar full-disk activity  The Solar Magnetic Field and Coronal Dynamics of the Eruption on 2007 May 19  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
Magnetic Helicity from Multipolar Regions on the Solar Surface
The width distribution of solar coronal loops and strands - Are we hitting rock bottom ?
Exoplanet predictions based on harmonic orbit resonances
Order out of randomness: Self-organization processes in astrophysics
Convection-driven generation of ubiquitous coronal waves
The minimum energy principle applied to Parker's coronal braiding and nanoflaring scenario
Self-organizing systems in planetary physics: Harmonic resonances of planet and moon orbits
Global energetics of solar flares: VIII. The Low-Energy Cutoff
Global Energetics of Solar Flares: VII. Aerodynamic Drag in Coronal Mass Ejections
Self-organized criticality in solar and stellar flares: Are extreme events scale-free ?
A Wavelet Based Approach to Solar-Terrestrial Coupling
Interplanetary Type IV Bursts
High resolution observations with Artemis-IV and the NRH. I. Type IV associated narrow-band bursts
Detection of spike-like structures near the front of type-II burstsA
High resolution observations with Artemis-JLS, (II) Type IV associated intermediate drift bursts
Oscillation of a small Hα surge in a solar polar coronal hole
Radio Observations of the January 20, 2005 X-Class Event
Fine Structure of Metric Type-IV Radio Bursts Observed with the ARTEMIS-IV Radio Spectrograph: Association with Flares and Coronal Mass Ejections
Spectral Analysis of the September 2017 Solar Energetic Particle Events
Solar Energetic Particle Events Observed by the PAMELA Mission

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