Study of temporal evolution of emission spectrum in a steeply rising submillimeter burst
文献类型：期刊论文
| 作者 | Li, Jian-Ping1,2 ; Zhou, Ai-Hua1,2; Wang, Xin-Dong3
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| 刊名 | RESEARCH IN ASTRONOMY AND ASTROPHYSICS
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| 出版日期 | 2016 |
| 卷号 | 16期号:1 |
| 关键词 | Sun: submillimeter burst Sun: energetic electrons Sun: radio source size |
| 英文摘要 | The temporal evolution of a spectrum during a steeply rising submillimeter (THz) burst that occurred on 2003 November 2 was investigated in detail for the first time. Observations show that the flux density of the THz spectrum increased steeply with frequency above 200 GHz. Their average rising rates reached a value of 235 sfu GHz(-1) (corresponding to spectral index alpha of 4.8) during the burst. The flux densities reached about 4 000 and 70 000 sfu at 212 and 405 GHz at the maximum phase, respectively. The emissions at 405 GHz maintained such a continuous high level that they largely exceeded the peak values of the microwave (MW) spectra during the main phase. Our studies suggest that only energetic electrons with a low-energy cutoff of similar to 1MeV and number density of similar to 10(6)-10(8) cm(-3) can produce such a strong and steeply rising THz component via gyrosynchrotron radiation based on numerical simulations of burst spectra in the case of a nonuniform magnetic field. The electron number density N, derived from our numerical fits to the THz temporal evolution spectra, increased substantially from 8 x 10(6) to 4 x 10(8) cm(-3), i.e., the N value increased 50 times during the rise phase. During the decay phase it decreased to 7 x 10(7) cm(-3), i.e., it decreased by about five times from the maximum phase. The total electron number decreased an order of magnitude from the maximum phase to the decay phase. Nevertheless, the variation in amplitude of N is only about one time in the MW emission source during this burst, and the total electron number did not decrease but increased by about 20% during the decay phase. Interestingly, we find that the THz source radius decreased by about 24% while the MW source radius, on the contrary, increased by 28% during the decay phase. |
| WOS标题词 | Science & Technology ; Physical Sciences |
| 类目[WOS] | Astronomy & Astrophysics |
| 研究领域[WOS] | Astronomy & Astrophysics |
| 关键词[WOS] | HARD X-RAY ; SOLAR-FLARES ; NONTHERMAL ELECTRONS ; NONUNIFORM SOURCE ; MICROWAVE ; COMPONENT ; WAVELENGTHS ; FREQUENCY ; RANGE ; GHZ |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000368088700008 |
| 源URL | [http://libir.pmo.ac.cn/handle/332002/16113]  |
| 专题 | 紫金山天文台_太阳活动的多波段观测研究团组 |
| 作者单位 | 1.Chinese Acad Sci, Key Lab Dark Matter & Space Astron, Nanjing 210008, Peoples R China 2.Chinese Acad Sci, Purple Mt Observ, Nanjing 210008, Peoples R China 3.Hohai Univ, Sch Publ Adm, Nanjing 210098, Jiangsu, Peoples R China |
| 推荐引用方式 GB/T 7714 | Li, Jian-Ping,Zhou, Ai-Hua,Wang, Xin-Dong. Study of temporal evolution of emission spectrum in a steeply rising submillimeter burst[J]. RESEARCH IN ASTRONOMY AND ASTROPHYSICS,2016,16(1). |
| APA | Li, Jian-Ping,Zhou, Ai-Hua,&Wang, Xin-Dong.(2016).Study of temporal evolution of emission spectrum in a steeply rising submillimeter burst.RESEARCH IN ASTRONOMY AND ASTROPHYSICS,16(1). |
| MLA | Li, Jian-Ping,et al."Study of temporal evolution of emission spectrum in a steeply rising submillimeter burst".RESEARCH IN ASTRONOMY AND ASTROPHYSICS 16.1(2016). |
入库方式： OAI收割
来源：紫金山天文台
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