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标题：Signatures of the non-Maxwellian κ-distributions in optically thin line spectra
其他标题：II. Synthetic Fe XVII–XVIII X-ray coronal spectra and predictions for the Marshall Grazing-Incidence X-ray Spectrometer (MaGIXS)
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作者：Jaroslav Dudík ; Elena Dzifčáková ; Giulio Del Zanna 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2019
卷号：626
DOI：10.1051/0004-6361/201935285
语种：English
出版社：EDP Sciences
摘要：Aims. We investigated the possibility of diagnosing the degree of departure from the Maxwellian distribution using the Fe XVII–Fe XVIIIspectra originating in plasmas in collisional ionization equilibrium, such as in the cores of solar active regions or microflares.Methods. The original collision strengths for excitation are integrated over the non-Maxwellian electronκ-distributions characterized by a high-energy tail. Synthetic X-ray emission line spectra were calculated for a range of temperatures andκ. We focus on the 6–24 Å spectral range to be observed by the upcoming Marshall Grazing-Incidence X-ray Spectrometer MaGIXS.Results. We find that many line intensity ratios are sensitive to bothTandκ. Best diagnostic options are provided if a ratio involving both Fe XVIIand Fe XVIIIis combined with another ratio involving lines formed within a single ion. The sensitivity of such diagnostics toκis typically a few tens of per cent. Much larger sensitivity, of about a factor of two to three, can be obtained if the Fe XVIII93.93 Å line observed by SDO/AIA is used in conjuction with the X-ray lines.Conclusions. We conclude that the MaGIXS instrument is well-suited for detection of departures from the Maxwellian distribution, especially in active region cores.
关键词：enSun: UV radiationSun: X-raysgamma raysSun: coronaradiation mechanisms: non-thermal