E-Print Archive

There are 4089 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
An Extreme Solar Event of 20 January 2005: Properties of the Flare and the Origin of Energetic Particles View all abstracts by submitter

Victor Grechnev   Submitted: 2008-06-30 03:14

The famous extreme solar and particle event of 20 January 2005 is analyzed from two perspectives. Firstly, using multi-spectral data, we study temporal, spectral, and spatial features of the main phase of the flare, when the strongest emissions from microwaves up to 200 MeV gamma-rays were observed. Secondly, we relate our results to a long-standing controversy on the origin of solar energetic particles (SEP) arriving at Earth, i.e., acceleration in flares, or shocks ahead of coronal mass ejections (CMEs). Our analysis shows that all electromagnetic emissions from microwaves up to 2.22 MeV line gamma-rays during the main flare phase originated within a compact structure located just above sunspot umbrae. In particular, a huge (~105 sfu) radio burst with a high frequency maximum at 30 GHz was observed, indicating the presence of a large number of energetic electrons in very strong magnetic fields. Thus, protons and electrons responsible for various flare emissions during its main phase were accelerated within the magnetic field of the active region. The leading, impulsive parts of the ground-level enhancement (GLE), and highest-energy gamma-rays identified with pi^0-decay emission, are similar and closely correspond in time. The origin of the pi^0-decay gamma-rays is argued to be the same as that of lower-energy emissions, although this is not proven. On the other hand, we estimate the sky-plane speed of the CME to be 2000-2600 km s-1, i.e., high, but of the same order as preceding non-GLE-related CMEs from the same active region. Hence, the flare itself rather than the CME appears to determine the extreme nature of this event. We therefore conclude that the acceleration, at least, to sub-relativistic energies, of electrons and protons, responsible for both the major flare emissions and the leading spike of SEP/GLE by 07 UT, are likely to have occurred nearly simultaneously within the flare region. However, our analysis does not rule out a probable contribution from particles accelerated in the CME-driven shock for the leading GLE spike, which seemed to dominate at later stages of the SEP event.

Authors: Grechnev, V. V., Kurt, V. G., Chertok, I. M., Uralov A. M. , Nakajima, H., Altyntsev A. T., Belov, A. V., Yushkov, B. Yu., Kuznetsov, S. N., Kashapova, L. K., Meshalkina, N. S., Prestage, N. P.
Projects: RHESSI,SoHO-EIT,SoHO-MDI,SoHO-LASCO,TRACE

Publication Status: Solar Physics, v. 252(1), pp. 149-177, 2008, DOI: 10.1007/s11207-008-9245-1. The original publication is available at www.springerlink.com
Last Modified: 2009-09-02 00:05
Go to main E-Print page  Coronal Tomography  Subject will be restored when possible  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
Fundamental Transverse Vibrations of the Active Region Solar Corona
Damping of slow magnetoacoustic oscillations by the misbalance between heating and cooling processes in the solar corona
Magnetic helicity and eruptivity in active region 12673
Impulsive coronal heating from large-scale magnetic rearrangements: from IRIS to SDO/AIA
Probing the effect of cadence on the estimates of photospheric energy and helicity injections in eruptive active region NOAA AR 11158
The birth of a coronal mass ejection
Oscillations of the baseline of solar magnetic field and solar irradiance on a millennial timescale
Chromospheric cannonballs on the Sun
Magnetic Helicity from Multipolar Regions on the Solar Surface
Exoplanet predictions based on harmonic orbit resonances
The width distribution of solar coronal loops and strands - Are we hitting rock bottom ?
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: 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

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