E-Print Archive

There are 4035 abstracts currently viewable.


Advanced Search
Main Page Add New E-Print Submitter
News Help/FAQ About Preferences
Manage Key Phrase
Imaging Spectroscopy on Preflare Coronal Nonthermal Sources Associated with the 2002 July 23 Flare View all abstracts by submitter

Ayumi Asai   Submitted: 2009-01-22 19:24

We present a detailed examination on the coronal nonthermal emissions during the preflare phase of the X4.8 flare that occurred on 2002 July 23. The microwave (17 GHz and 34 GHz) data obtained with Nobeyama Radioheliograph, at Nobeyama Solar Radio Observatory and the hard X-ray (HXR) data taken with {it Reuven Ramaty High Energy Solar Spectroscopic Imager} obviously showed nonthermal sources that are located above the flare loops during the preflare phase. We performed imaging spectroscopic analyses on the nonthermal emission sources both in microwaves and in HXRs, and confirmed that electrons are accelerated from several tens of keV to more than 1~MeV even in this phase. If we assume the thin-target model for the HXR emission source, the derived electron spectral indices (sim 4.7) is the same value as that from microwaves (sim 4.7) within the observational uncertainties, which implies that the distribution of the accelerated electrons follows a single power-law. The number density of the microwave-emitting electrons is, however, larger than that of the HXR-emitting electrons, unless we assume low ambient plasma density of about 1.0 imes 109~cm-3 for the HXR-emitting region. If we adopt the thick-target model for the HXR emission source, on the other hand, the electron spectral index (sim 6.7) is much different, while the gap of the number density of the accelerated electrons is somewhat reduced.

Authors: Ayumi Asai, Hiroshi Nakajima, Masumi Shimojo, Takaaki Yokoyama, Satoshi Masuda, Säm Krucker
Projects: RHESSI

Publication Status: ApJ (accepted)
Last Modified: 2009-01-23 09:36
Go to main E-Print page  Acoustic wave propagation in the solar sub-photosphere with localised magnetic field concentration: effect of magnetic tension  Are Coronal Loops Isothermal or Multithermal? Yes!  Edit Entry  Download Preprint  Submitter's Homepage 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
Why Does the Solar Corona Abnormally Rotate Faster Than the Photosphere?
Impacts On Proton Fluxes Observed During Different Interplanetary Conditions
Coronal Loop Seismology Using Standing Kink Oscillations With a Lookup Table
Data-Optimized Coronal Field Model: I. Proof of Concept
Coronal Bright Points
Difference of source regions between fast and slow coronal mass ejections
Invited Review: Signatures of Magnetic Flux Ropes in the Low Solar Atmosphere Observed in High Resolution
Do Kepler superflare stars really include slowly-rotating Sun-like stars ? - Results using APO 3.5m telescope spectroscopic observations and Gaia-DR2 data -
Magnetically Induced Current Piston for Generating Extreme-ultraviolet Fronts in the Solar Corona
Magnetic Field Dynamics and Varying Plasma Emission in Large-scale Coronal Loops
Nonlinear Evolution of Ion Kinetic Instabilities in the Solar Wind
What determines the X-ray intensity and duration of a solar flare?
Fast Magnetoacoustic Wave Trains with Time-dependent Drivers
Three-dimensional reconstruction of CME-driven shock-streamer interaction from radio observations: a different take on the diagnostics of coronal magnetic fields
The soft X-ray spectrometer polarimeter SolpeX
Variable emission mechanism of a Type IV radio burst
Inference of magnetic field strength and density from damped transverse coronal waves
Frequency-Distance Structure of Solar Radio Sources Observed by LOFAR
The birth of a coronal mass ejection
Properties of slow magnetoacoustic oscillations of solar coronal loops by multi-instrumental observations

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