X-Ray Spectra from Plasmas with High-energy Electrons: κ-distributions and e?–e? Bremsstrahlung
文献类型：期刊论文
| 作者 | Cui,Xiaohong2,3; Foster,Adam R.3; Yuasa,Takayuki1; Smith,Randall K.3 |
| 刊名 | The Astrophysical Journal
 |
| 出版日期 | 2019-12-18 |
| 卷号 | 887期号:2 |
| ISSN号 | 0004-637X |
| 关键词 | White dwarf stars Atomic physics Atomic spectroscopy X-ray astronomy Laboratory astrophysics Nonthermal radiation sources |
| DOI | 10.3847/1538-4357/ab5304 |
| 英文摘要 | Abstract Shocks, turbulence, and winds all influence the electron velocity distribution in hot plasmas, exciting lower-energy electrons and generating a high-energy (typically power-law) tail. This effect, typically described as a κ distribution can affect both the line and continuum X-ray spectra emitted by the plasma. Hahn & Savin proposed a “Maxwellian decomposition” to generate the rate coefficients of κ distributions. Using their method and the AtomDB atomic database, we have developed a general model to calculate the emission from a plasma with a κ distribution. We compare our κ results for the charge state distribution and spectra of oxygen with those from KAPPA package with the ion data available within the CHIANTI atomic database. Sufficiently energetic electrons, created either in a κ distribution or merely a very hot Maxwellian plasma, can also emit via electron–electron (e–e) bremsstrahlung, a process not previously included in AtomDB. We have added this process to AtomDB and apply it to calculate the temperature gradients, as well as the total spectra from the post-shock regions of an accreting magnetic cataclysmic variable. We find the contribution of e–e bremsstrahlung to the total spectra exceeds 10% at KT?～?100 keV, with the total emissivity in the post-shock accretion stream differing by more than 10% at energies above 60 keV. |
| 语种 | 英语 |
| 出版者 | The American Astronomical Society |
| WOS记录号 | IOP:0004-637X-887-2-AB5304 |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/28682]  |
| 专题 | 中国科学院国家天文台 |
| 作者单位 | 1.Nishina Center for Accelerator-based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; yuasatakayuki@gmail.com 2.National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing, People’s Republic of China 3.Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138, USA |
| 推荐引用方式 GB/T 7714 | Cui,Xiaohong,Foster,Adam R.,Yuasa,Takayuki,et al. X-Ray Spectra from Plasmas with High-energy Electrons: κ-distributions and e?–e? Bremsstrahlung[J]. The Astrophysical Journal,2019,887(2). |
| APA | Cui,Xiaohong,Foster,Adam R.,Yuasa,Takayuki,&Smith,Randall K..(2019).X-Ray Spectra from Plasmas with High-energy Electrons: κ-distributions and e?–e? Bremsstrahlung.The Astrophysical Journal,887(2). |
| MLA | Cui,Xiaohong,et al."X-Ray Spectra from Plasmas with High-energy Electrons: κ-distributions and e?–e? Bremsstrahlung".The Astrophysical Journal 887.2(2019). |
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来源：国家天文台
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