On the Shock Source of Sustained Gamma-Ray Emission from the Sun
On the Shock Source of Sustained Gamma-Ray Emission from the Sun
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太阳持续伽马射线激波源
DOI：
10.1088/1742-6596/1332/1/012004
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
H. Xie
中科院分区：
文献类型：
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作者：
N. Gopalswamy;P. Makela;S. Yashiro;A. Lara;S. Akiyama;H. Xie
最近的研究表明，太阳喷发中在时间和空间上扩展的γ射线辐射是由日冕物质抛射(CME)驱动的激波在太阳上沉淀的300 MeV质子引起的。γ射线是当300 MeV质子与色球中的质子碰撞时，质子-质子相互作用中产生的中性介子衰变的结果。证据来自持续伽马射线发射(SGRE)的持续时间与相关的星际(IP)II型射电爆发之间的密切相关。在这篇文章中，我们提供了进一步的证据，支持在日冕物质抛射驱动的激波中加速的质子向太阳传播，在色球中沉淀，产生观测到的SGRE。我们介绍了SGRE事件以及与之相关的日冕物质抛射、耀斑和II型射电爆发的统计特性。结果表明，SGRE日冕物质抛射与地面增强事件有相似之处。CME速度与SGRE通量有很好的相关性。较高的CME速度是SGRE发生的重要条件，而耀斑大小则不是。在这些结果的基础上，我们提出了一个示意性模式，说明了与CME磁绳激波结构有关的SGRE的时空扩展性质。
It has recently been shown that the spatially and temporally extended γ-ray emission in solar eruptions are caused by >300 MeV protons precipitating on the Sun from shocks driven by coronal mass ejections (CMEs). The γ-rays result from the decay of neutral pions produced in the proton-proton interaction when the >300 MeV protons collide with those in the chromosphere. The evidence comes from the close correlation between the durations of the sustained gamma-ray emission (SGRE) and the associated interplanetary (IP) type II radio bursts. In this paper, we provide further evidence that support the idea that protons accelerated in IP shocks driven by CMEs propagate toward the Sun, precipitate in the chromosphere to produce the observed SGRE. We present the statistical properties of the SGRE events and the associated CMEs, flares, and type II radio bursts. It is found that the SGRE CMEs are similar to those associated with ground level enhancement events. The CME speed is well correlated with the SGRE fluence. High CME speed is an important requirement for the occurrence of SGRE, while the flare size is not. Based on these results, we present a schematic model illustrating the spatially and temporally extended nature of SGRE related to the CME flux rope-shock structure.