E-Print Archive

There are 3898 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
Statistics, Morphology, and Energetics of Ellerman Bombs View all abstracts by submitter

Manolis K. Georgoulis   Submitted: 2002-04-08 16:42

We investigate the statistical properties of Ellerman bombs in the dynamic emerging flux region NOAA 8844, underneath an expanding arch filament system. High-resolution chromospheric Hα filtergrams (spatial resolution 0.8arcsec), as well as photospheric vector magnetograms (spatial resolution 0.5arcsec), and Dopplergrams, have been acquired by the balloon-borne Flare Genesis Experiment. Hα observations reveal the first ``seeing-free'' data set on Ellerbombs and one of the largest samples of these events. We find that Ellerman bombs occur and recur in preferential locations in the low chromosphere, either above, or in the absence of, photospheric neutral magnetic lines. Ellerman bombs are associated with photospheric downflows and their loci follow the transverse mass flows on the photosphere. They are small-scale events, with typical size 1.8 imes 1.1;arcsec^2, but this size depends on the instrumental resolution. A large number of Ellerman bombs are probably undetected, due to limited spatial resolution. Ellerman bombs occur in clusters which exhibit fractal properties. The fractal dimension, with an average value sim 1.4, does not change significantly in the course of time. Typical parameters of Ellerman bombs are interrelated and obey power-law distribution functions, as in case of flaring and sub-flaring activity. We find that Ellerman bombs may occur on separatrix, or quasi-separatrix, layers, in the low chromosphere. A plausible triggering mechanism of Ellerman bombs is stochastic magnetic reconnection caused by the turbulent evolution of the low-lying magnetic fields and the continuous re-shaping of separatrix layers. The total energies of Ellerman bombs are estimated in the range (1027,1028);erg, the temperature enhancement in the radiating volume is sim 2 imes 103;K and the timescale of radiative cooling is short, of the order of a few seconds. The distribution function of the energies of Ellerman bombs exhibits a power-law shape with an index sim -2.1. This suggests that Ellerman bombs may contribute significantly to the heating of the low chromosphere in emerging flux regions.

Authors: M. K. Georgoulis, D. M. Rust, P. N. Bernasconi, and B. Schmieder
Projects:

Publication Status: ApJ (in press)
Last Modified: 2002-04-08 16:42
Go to main E-Print page  Coronal mass ejections and their association to active region flaring.  OSCILLATING HOT LOOPS OBSERVED BY SUMER  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
An Event-Based Verification Scheme for the Real-Time Flare Detection System at Kanzelhöhe Observatory
Computation of Relative Magnetic Helicity in Spherical Coordinates
Some characteristics of the GLE on 10 September 2017
Quasi-periodic Pulsations in a Solar Microflare
Homologous large-amplitude Nonlinear fast-mode Magnetosonic Waves Driven by Recurrent Coronal Jets
EUV Waves Driven by Sudden Expansion of Transequatorial Loops Caused by Solar Coronal Jets
Dispersively formed quasi-periodic fast magnetosonic wavefronts due to the eruption of a nearby mini-filament
Mini-filament Eruptions Triggering Confined Solar Flares Observed by ONSET and SDO
LOFAR observations of fine spectral structure dynamics in type IIIb radio bursts
Critical magnetic field strengths for solar coronal plumes in quiet regions and coronal holes?
Does Nearby Open Flux Affect the Eruptivity of Solar Active Regions?
Cyclic Changes of the Sun's Seismic Radius
Onset of Photospheric Impacts and Helioseismic Waves in X9.3 Solar Flare of September 6, 2017
Solar Cycle Variations of Rotation and Asphericity in the Near-Surface Shear Layer
Solar coronal loop dynamics near the null point above active region NOAA 2666
Energetics of small electron acceleration episodes in the solar corona from radio noise storm observations
The origin of the modulation of the radio emission from the solar corona by a fast magnetoacoustic wave
Indirect solar wind measurements using archival cometary tail observations
Helium abundance and speed difference between helium ions and protons in the solar wind from coronal holes, active regions, and quiet Sun
Always a Farm Boy

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