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arXiv 1902.01140astro-ph.SR
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一个IV型射电爆发的可变发射机制

Variable emission mechanism of a Type IV radio burst

D. E. Morosan, E. K. J. Kilpua, E. P. Carley, C. Monstein

摘要:

上下文太阳是一颗活跃的恒星,也是太阳系中最大的爆炸源,如耀斑和日冕物质抛射(CME)。耀斑和日冕物质抛射是强大的粒子加速器,可以通过各种发射机制产生射电辐射。目的。CME通常伴随着IV型射电爆发,这些射电爆发在分米波和米波的动态光谱中被观察到连续发射,但它们的发射机制可能因事件而异。在这里,我们的目标是确定2011年9月22日伴随耀斑和CME的复杂IV型爆发的发射机制。方法.我们使用来自Nançay射电日像仪的无线电成像,来自e-Callisto网络的光谱数据,ARTEMIS,Ondrejov和Phoenix 3光谱仪结合美国宇航局太阳动力学天文台的极紫外观测,分析IV型射电爆发并确定其发射机制。结果我们发现IV型射电爆发的发射机制随时间而变化。我们确定了IV型射电爆发中的两个组成部分:早期静止的IV型,显示出陀螺同步加速器的行为,以及后来移动的IV型爆发,覆盖相同的频带。该第二组分具有相干发射机制。基本等离子体发射和电子回旋脉塞发射作为可能的发射机制产生的移动IV型爆发进一步调查。结论.因此,IV型爆发是复杂的射电爆发,其中多种发射机制可以有助于产生动态光谱中观察到的宽带连续谱。成像光谱在一个宽的频带是必要的,以确定在动态光谱中观察到的IV型爆发的发射机制。

英文摘要:

Context. The Sun is an active star and the source of the largest explosions in the solar system, such as flares and coronal mass ejections (CMEs). Flares and CMEs are powerful particle accelerators that can generate radio emission through various emission mechanisms. Aims. CMEs are often accompanied by Type IV radio bursts that are observed as continuum emission in dynamic spectra at decimetric and metric wavelengths, but their emission mechanism can vary from event to event. Here, we aim to determine the emission mechanism of a complex Type IV burst that accompanied the flare and CME on 22 September 2011. Methods. We used radio imaging from the Nançay Radioheliograph, spectroscopic data from the e-Callisto network, ARTEMIS, Ondrejov, and Phoenix3 spectrometers combined with extreme-ultraviolet observations from NASA's Solar Dynamic Observatory to analyse the Type IV radio burst and determine its emission mechanism. Results. We show that the emission mechanism of the Type IV radio burst changes over time. We identified two components in the Type IV radio burst: an earlier stationary Type IV showing gyro-synchrotron behaviour, and a later moving Type IV burst covering the same frequency band. This second component has a coherent emission mechanism. Fundamental plasma emission and the electroncyclotron maser emission are further investigated as possible emission mechanisms for the generation of the moving Type IV burst. Conclusions. Type IV bursts are therefore complex radio bursts, where multiple emission mechanisms can contribute to the generation of the wide-band continuum observed in dynamic spectra. Imaging spectroscopy over a wide frequency band is necessary to determine the emission mechanisms of Type IV bursts that are observed in dynamic spectra.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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