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Title: Verification of coronal loop diagnostics using realistic three-dimensional hydrodynamic models

Many different techniques have been used to characterize the plasma in the solar corona: density-sensitive spectral line ratios are used to infer the density, the evolution of coronal structures in different passbands is used to infer the temperature evolution, and the simultaneous intensities measured in multiple passbands are used to determine the emission measure distributions. All these analysis techniques assume that the intensity of the structures can be isolated through background subtraction. In this paper, we use simulated observations from a three-dimensional hydrodynamic simulation of a coronal active region to verify these diagnostics. The density and temperature from the simulation are used to generate images in several passbands and spectral lines. We identify loop structures in the simulated images and calculate the background. We then determine the density, temperature, and emission measure distribution as a function of time from the observations and compare these with the true temperature and density of the loop. We find that the overall characteristics of the temperature, density, and emission measure are recovered by the analysis methods, but the details are not. For instance, the emission measure curves calculated from the simulated observations are much broader than the true emission measure distribution, though the averagemore » temperature evolution is similar. These differences are due, in part, to a limitation of the analysis methods, but also to inadequate background subtraction.« less
Authors:
 [1] ; ; ;  [2] ;  [3]
  1. NASA Marshall Space Flight Center, ZP 13, Huntsville, AL 35812 (United States)
  2. Predictive Science, Inc., 9990 Mesa Rim Road, Suite 170, San Diego, CA 92121-2910 (United States)
  3. Department of Physics and Astronomy, University of California, 4129 Reines Hall, Irvine, CA 92697 (United States)
Publication Date:
OSTI Identifier:
22370223
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 795; 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; COMPARATIVE EVALUATIONS; DENSITY; DISTRIBUTION; EMISSION; GAMMA RADIATION; HYDRODYNAMIC MODEL; PLASMA; SIMULATION; SOLAR CORONA; STAR EVOLUTION; SUN; THREE-DIMENSIONAL CALCULATIONS; TIME DEPENDENCE; ULTRAVIOLET RADIATION; VERIFICATION; X RADIATION