E-Print Archive

There are 4002 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
Looptop Hard X-Ray Emission In Solar Flares: Images And Statistics View all abstracts by submitter

Timothy Donaghy   Submitted: 2001-12-13 14:24

The discovery of hard X-ray sources near the top of a flaring loop by the HXT instrument on board the YOHKOH satellite represents a significant progress towards the understanding of the basic processes driving solar flares. In this paper we extend the previous study of limb flares by Masuda (1994) by including all YOHKOH observations up through August 1998. We report that from October 1991 to August 1998, YOHKOH observed 20 X-ray bright limb flares (where we use the same selection criteria as Masuda), of which we have sufficient data to analyze 18 events, including 8 previously unanalyzed flares. Of these 18 events, 15 show detectable impulsive looptop emission. Considering that the finite dynamic range (about a decade) of the detection introduces a strong bias against observing comparatively weak looptop sources, we conclude that looptop emission is a common feature of all flares. We summarize the observations of the footpoint to looptop flux ratio and the spectral indices. We present light curves and images of all the important newly analyzed limb flares. Whenever possible we present results for individual pulses in multipeak flares and for different loops for multiloop flares. We then discuss the statistics of the fluxes and spectral indices of the looptop and footpoint sources taking into account observational selection biases. The importance of these observations (and those expected from the scheduled HESSI satellite with its superior angular spectral and temporal resolution) in constraining acceleration models and parameters is discussed briefly.

Authors: Vahé Petrosian, Timothy Q. Donaghy & James M. McTiernan
Projects:

Publication Status: accepted ApJ
Last Modified: 2001-12-13 14:24
Go to main E-Print page  Location of narrowband spikes in solar flares  LASCO and EIT Observations of the Bastille Day 2000 Solar Storm  Edit Entry  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
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