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Turbulent and directed plasma motions in solar flaresAn improved method for fitting asymmetric soft X-ray line profiles from solar flares is presented. A two-component model is used where one component represents the total emission from directed upflow plasma and the other the emission from the plasma at rest. Unlike previous methods, the width of the moving component is independent from that of the stationary component. Time variations of flare plasma characteristics (i.e., temperature, emission measure of moving and stationary plasma, upflow and turbulent velocities) are derived from the Ca XIX and Fe XXV spectra recorded by the Bent Crystal Spectrometer on the Solar Maximum Mission. The fitting technique provides a statistical estimation for the uncertainties in the fitting parameters. The relationship between the directed and turbulent motions has been studied, and a correlation of the random and directed motions has been found in some flares with intensive plasma upflows. Mean temperatures of the upflowing and stationary plasmas are compared for the first time from ratios of calcium to iron X-ray line intensities. Finally, evidence for turbulent motions and the possibility of plasma upflow late into the decay phase is presented and discussed.
Document ID
19890066503
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Fludra, A.
(University Coll. Dorking, United Kingdom)
Bentley, R. D.
(London, University College, Dorking, United Kingdom)
Lemen, J. R.
(Lockheed Research Laboratories Palo Alto, CA, United States)
Jakimiec, J.
(Wroclaw Uniwersytet, Poland)
Sylwester, J.
(Polska Akademia Nauk Centrum Badan Kosmicznych, Wroclaw, Poland)
Date Acquired
August 14, 2013
Publication Date
September 15, 1989
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 344
ISSN: 0004-637X
Subject Category
Solar Physics
Accession Number
89A53874
Funding Number(s)
CONTRACT_GRANT: NAS5-28713
Distribution Limits
Public
Copyright
Other

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