Subsecond Time Evolution of Type III Solar Radio Burst Sources at Fundamental and Harmonic Frequencies
文献类型：期刊论文
| 作者 | Chen,Xingyao1,2 ; Kontar,Eduard P.1; Chrysaphi,Nicolina1; Jeffrey,Natasha L. S.3; Gordovskyy,Mykola4; Yan,Yihua2,5; Tan,Baolin2,5
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| 刊名 | The Astrophysical Journal
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| 出版日期 | 2020-12-01 |
| 卷号 | 905期号:1 |
| 关键词 | Solar radio emission Interplanetary turbulence Radio bursts Solar radio flares |
| ISSN号 | 0004-637X |
| DOI | 10.3847/1538-4357/abc24e |
| 英文摘要 | Abstract Recent developments in astronomical radio telescopes opened new opportunities in imaging and spectroscopy of solar radio bursts at subsecond timescales. Imaging in narrow frequency bands has revealed temporal variations in the positions and source sizes that do not fit into the standard picture of type III solar radio bursts, and require a better understanding of radio-wave transport. In this paper, we utilize 3D Monte Carlo ray-tracing simulations that account for the anisotropic density turbulence in the inhomogeneous solar corona to quantitatively explain the image dynamics at the fundamental (near plasma frequency) and harmonic (double) plasma emissions observed at ～32?MHz. Comparing the simulations with observations, we find that anisotropic scattering from an instantaneous emission point source can account for the observed time profiles, centroid locations, and source sizes of the fundamental component of type III radio bursts (generated where f pe?≈?32 MHz). The best agreement with observations is achieved when the ratio of the perpendicular to the parallel component of the wavevector of anisotropic density turbulence is around 0.25. Harmonic emission sources observed at the same frequency (～32 MHz, but generated where f pe?≈?16 MHz) have apparent sizes comparable to those produced by the fundamental emission, but demonstrate a much slower temporal evolution. The simulations of radio-wave propagation make it possible to quantitatively explain the variations of apparent source sizes and positions at subsecond timescales both for the fundamental and harmonic emissions, and can be used as a diagnostic tool for the plasma turbulence in the upper corona. |
| 语种 | 英语 |
| WOS记录号 | IOP:0004-637X-905-1-ABC24E |
| 出版者 | The American Astronomical Society |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/57745]  |
| 专题 | 中国科学院国家天文台 |
| 作者单位 | 1.School of Physics & Astronomy, University of Glasgow, Glasgow G12 8QQ, UK 2.Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, People's Republic of China 3.Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Newcastle upon Tyne NE1 8ST, UK 4.School of Physics & Astronomy, University of Manchester, Manchester M13 9PL, UK 5.School of Astronomy and Space Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China |
| 推荐引用方式 GB/T 7714 | Chen,Xingyao,Kontar,Eduard P.,Chrysaphi,Nicolina,et al. Subsecond Time Evolution of Type III Solar Radio Burst Sources at Fundamental and Harmonic Frequencies[J]. The Astrophysical Journal,2020,905(1). |
| APA | Chen,Xingyao.,Kontar,Eduard P..,Chrysaphi,Nicolina.,Jeffrey,Natasha L. S..,Gordovskyy,Mykola.,...&Tan,Baolin.(2020).Subsecond Time Evolution of Type III Solar Radio Burst Sources at Fundamental and Harmonic Frequencies.The Astrophysical Journal,905(1). |
| MLA | Chen,Xingyao,et al."Subsecond Time Evolution of Type III Solar Radio Burst Sources at Fundamental and Harmonic Frequencies".The Astrophysical Journal 905.1(2020). |
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来源：国家天文台
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