The Acceleration of Energetic Particles at Coronal Shocks and Emergence of a Double Power-law Feature in Particle Energy Spectra
The Acceleration of Energetic Particles at Coronal Shocks and Emergence of a Double Power-law Feature in Particle Energy Spectra
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日冕震中高能粒子的加速和粒子能量谱中双幂律特征的出现
DOI：
10.3847/1538-4357/ab3848
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发表时间：
2019-07
影响因子：
4.9
通讯作者：
Giacalone Joe
中科院分区：
文献类型：
--
作者：
Kong Xiangliang;Guo Fan;Chen Yao;Giacalone Joe
通过求解沿着和跨磁场的空间扩散的帕克输运方程，我们提出了数值模拟的粒子加速在日冕冲击传播通过流光状磁场。我们表明，在冲击的高能粒子强度是最大的位置，取决于粒子的能量和时间。粒子加速到100 MeV以上主要发生在激波-流光相互作用区，这是由于垂直激波几何形状和封闭磁场的俘获效应。粒子谱的径向磁场中的比较表明，在100 MeV（200 MeV）的强度增强超过一个数量级（两个数量级）。这表明，流状磁场可能是产生大的太阳高能粒子事件的一个重要因素。我们还表明，在模拟域集成的能量谱由两个不同的幂律。进一步的分析表明，它可能是两种不同的人口在流光和开放领域的加速，其中的加速率有很大的不同的混合物。我们的计算还表明，粒子谱的影响相当大的一些参数，如流光倾斜角，粒子的空间扩散系数，和冲击压缩比。低能能谱与标准的扩散激波加速理论符合得很好，断裂能的范围从10.1 MeV到10.90 MeV，高能能谱可以扩展到10.1 GeV，斜率为10.2 -3。
We present numerical modeling of particle acceleration at coronal shocks propagating through a streamer-like magnetic field by solving the Parker transport equation with spatial diffusion both along and across the magnetic field. We show that the location on the shock where the high-energy particle intensity is the largest, depends on the energy of the particles and on time. The acceleration of particles to more than 100 MeV mainly occurs in the shock-streamer interaction region, due to perpendicular shock geometry and the trapping effect of closed magnetic fields. A comparison of the particle spectra to that in a radial magnetic field shows that the intensity at 100 MeV (200 MeV) is enhanced by more than one order (two orders) of magnitude. This indicates that the streamer-like magnetic field can be an important factor in producing large solar energetic particle events. We also show that the energy spectrum integrated over the simulation domain consists of two different power laws. Further analysis suggests that it may be a mixture of two distinct populations accelerated in the streamer and open field regions, where the acceleration rate differs substantially. Our calculations also show that the particle spectra are affected considerably by a number of parameters, such as the streamer tilt angle, particle spatial diffusion coefficient, and shock compression ratio. While the low-energy spectra agree well with standard diffusive shock acceleration theory, the break energy ranges from ∼1 MeV to ∼90 MeV and the high-energy spectra can extend to ∼1 GeV with a slope of ∼2–3.
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DOI：
10.3847/1538-4357/833/1/45
发表时间：
2016-05
期刊：
The Astrophysical Journal
影响因子：
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作者：
A. Rouillard;I. Plotnikov;R. Pinto;M. Tirole;M. Lavarra;P. Zucca;R. Vainio;A. Tylka;A. Vourlidas-A.
通讯作者：
A. Rouillard;I. Plotnikov;R. Pinto;M. Tirole;M. Lavarra;P. Zucca;R. Vainio;A. Tylka;A. Vourlidas-A.
DOI：
10.1088/0004-637x/720/1/130
发表时间：
2010-09
期刊：
The Astrophysical Journal
影响因子：
--
作者：
A. Bemporad;S. Mancuso
通讯作者：
A. Bemporad;S. Mancuso
日冕物质抛射-日冕射线相互作用产生的太阳 II 型射电爆发：同时射电和极紫外成像
影响因子：
4.9
作者：
Chen Yao;Du Guohui;Feng Li;Feng Shiwei;Kong Xiangliang;Guo Fan;Wang Bing;Li Gang
通讯作者：
Li Gang
影响因子：
2.8
作者：
B. Bavassano;M. Dobrowolny;G. Fanfoni;F. Mariani;N. Ness
通讯作者：
B. Bavassano;M. Dobrowolny;G. Fanfoni;F. Mariani;N. Ness
影响因子：
--
作者：
J. Giacalone;J. Jokipii
通讯作者：
J. Giacalone;J. Jokipii