DIFFERENTIAL EMISSION MEASURE ANALYSIS OF A POLAR CORONAL HOLE DURING THE SOLAR MINIMUM IN 2007

AbstractWe use Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) data to reconstruct the plasma properties from differential emission measure (DEM) analysis for a previously studied long-lived, low-latitude coronal hole (CH) over its lifetime of ten solar rotations. We initially obtain a non-isothermal DEM distribution with a dominant component centered around 0.9 MK and a secondary smaller component at 1.5 – 2.0 MK. We find that deconvolving the data with the instrument point spread function (PSF) to account for long-range scattered light reduces the secondary hot component. Using the 2012 Venus transit and a 2013 lunar eclipse to test the efficiency of this deconvolution, significant amounts of residual stray light are found for the occulted areas. Accounting for this stray light in the error budget of the different AIA filters further reduces the secondary hot emission, yielding CH DEM distributions that are close to isothermal with the main contribution centered around 0.9 MK. Based on these DEMs, we analyze the evolution of the emission measure (EM), density, and averaged temperature during the CH’s lifetime. We find that once the CH is clearly observed in EUV images, the bulk of the CH plasma reveals a quite constant state, i.e. temperature and density reveal no major changes, whereas the total CH area and the photospheric magnetic fine structure inside the CH show a distinct evolutionary pattern. These findings suggest that CH plasma properties are mostly “set” at the CH formation or/and that all CHs have similar plasma properties.

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DERIVING PLASMA DENSITIES AND ELEMENTAL ABUNDANCES FROM SERTS DIFFERENTIAL EMISSION MEASURE ANALYSIS

The Astrophysical Journal ◽

10.1088/0004-637x/757/1/17 ◽

2012 ◽

Vol 757 (1) ◽

pp. 17 ◽

Cited By ~ 4

Author(s):

J. T. Schmelz ◽

J. A. Kimble ◽

J. L. R. Saba

Keyword(s):

Emission Measure ◽

Differential Emission Measure ◽

Elemental Abundances ◽

Measure Analysis

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Overview of XRT performance and first results

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308015044 ◽

2007 ◽

Vol 3 (S247) ◽

pp. 326-336

Author(s):

Antonia Savcheva ◽

Keyword(s):

Fine Structure ◽

Coronal Holes ◽

Emission Measure ◽

Active Regions ◽

Potential Fields ◽

Differential Emission Measure ◽

Short Introduction ◽

X Ray ◽

First Results ◽

Measure Analysis

AbstractIn this review we present a short introduction to the X-ray Telescope on Hinode. We discuss its capabilities and new features and compare it with Yohkoh SXT. We also discuss some of the first results that include observations of X-ray jets in coronal holes, shear change in flares, sigmoid eruptions and evolution, application of filter ratios and differential emission measure analysis, structure of active regions, fine structure of X-ray bright points, and modeling non-potential fields around filaments. Finally, we describe how XRT works with other ground and space-based instrumentation, in particular with TRACE, EIS, SOT, and SOLIS.

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