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Title: OBSERVATIONS OF THERMAL FLARE PLASMA WITH THE EUV VARIABILITY EXPERIMENT

Abstract

One of the defining characteristics of a solar flare is the impulsive formation of very high temperature plasma. The properties of the thermal emission are not well understood, however, and the analysis of solar flare observations is often predicated on the assumption that the flare plasma is isothermal. The EUV Variability Experiment (EVE) on the Solar Dynamics Observatory provides spectrally resolved observations of emission lines that span a wide range of temperatures (e.g., Fe XV-Fe XXIV) and allow for thermal flare plasma to be studied in detail. In this paper we describe a method for computing the differential emission measure distribution in a flare using EVE observations and apply it to several representative events. We find that in all phases of the flare the differential emission measure distribution is broad. Comparisons of EVE spectra with calculations based on parameters derived from the Geostationary Operational Environmental Satellites soft X-ray fluxes indicate that the isothermal approximation is generally a poor representation of the thermal structure of a flare.

Authors:
;  [1];  [2]
  1. Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)
  2. School of Physics, Astronomy, and Computational Sciences, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)
Publication Date:
OSTI Identifier:
22127076
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 770; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; APPROXIMATIONS; COMPARATIVE EVALUATIONS; DISTRIBUTION; GOES SATELLITES; PLASMA; SOFT X RADIATION; SOLAR FLARES; SPECTRA; SUN; TEMPERATURE RANGE 1000-4000 K

Citation Formats

Warren, Harry P., Doschek, George A., and Mariska, John T. OBSERVATIONS OF THERMAL FLARE PLASMA WITH THE EUV VARIABILITY EXPERIMENT. United States: N. p., 2013. Web. doi:10.1088/0004-637X/770/2/116.
Warren, Harry P., Doschek, George A., & Mariska, John T. OBSERVATIONS OF THERMAL FLARE PLASMA WITH THE EUV VARIABILITY EXPERIMENT. United States. doi:10.1088/0004-637X/770/2/116.
Warren, Harry P., Doschek, George A., and Mariska, John T. Thu . "OBSERVATIONS OF THERMAL FLARE PLASMA WITH THE EUV VARIABILITY EXPERIMENT". United States. doi:10.1088/0004-637X/770/2/116.
@article{osti_22127076,
title = {OBSERVATIONS OF THERMAL FLARE PLASMA WITH THE EUV VARIABILITY EXPERIMENT},
author = {Warren, Harry P. and Doschek, George A. and Mariska, John T.},
abstractNote = {One of the defining characteristics of a solar flare is the impulsive formation of very high temperature plasma. The properties of the thermal emission are not well understood, however, and the analysis of solar flare observations is often predicated on the assumption that the flare plasma is isothermal. The EUV Variability Experiment (EVE) on the Solar Dynamics Observatory provides spectrally resolved observations of emission lines that span a wide range of temperatures (e.g., Fe XV-Fe XXIV) and allow for thermal flare plasma to be studied in detail. In this paper we describe a method for computing the differential emission measure distribution in a flare using EVE observations and apply it to several representative events. We find that in all phases of the flare the differential emission measure distribution is broad. Comparisons of EVE spectra with calculations based on parameters derived from the Geostationary Operational Environmental Satellites soft X-ray fluxes indicate that the isothermal approximation is generally a poor representation of the thermal structure of a flare.},
doi = {10.1088/0004-637X/770/2/116},
journal = {Astrophysical Journal},
number = 2,
volume = 770,
place = {United States},
year = {Thu Jun 20 00:00:00 EDT 2013},
month = {Thu Jun 20 00:00:00 EDT 2013}
}