Abstract
In the standard method of electron density determination for soft X-ray (SXR) flare kernels, it is necessary to assume what the extent is of a kernel along the line of sight. This is a source of significant uncertainty of the obtained densities.
In our previous paper (Ba̧k-Stȩślicka and Jakimiec, Solar Phys. 231, 95, 2005) we have proposed a new method of deriving electron density, in which it is not necessary to assume what the extent of a kernel along the line of sight is. This new method is based on the idea that many flares, during their decay phase, can be described with a sequence of steady-state models [quasi-steady-state (QSS) evolution] and then a scaling law, derived for steady-state models, can be used to determine the electron density.
The aim of the present paper is: i) to improve both methods of density determination, and ii) to compare the densities obtained with the two methods. We have selected a number of flares which showed QSS evolution during their decay phase. For these flares the electron density, N, has been derived by means of both the standard method and with our QSS method. Comparison of the N values obtained with the two different methods allowed us: i) to test the obtained densities, ii) to evaluate the volume filling factor of the SXR emitting plasma.
Generally, we have found good agreement (no large systematic differences) between the values of electron density obtained with the two methods, though for some cases the values differed by up to a factor of two. For most flare kernels the filling factor turned out to be about one near the flare maximum.
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References
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Open Access This is an open access article distributed under the terms of the Creative Commons Attribution Noncommercial License (https://creativecommons.org/licenses/by-nc/2.0), which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
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Jakimiec, J., Ba̧k-Stȩślicka, U. Determination of Electron Density and Filling Factor for Soft X-Ray Flare Kernels. Sol Phys 272, 91 (2011). https://doi.org/10.1007/s11207-011-9812-8
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DOI: https://doi.org/10.1007/s11207-011-9812-8