Simulating the interaction between supra-thermal particles and the magnetic field in astrophysical shocks
Simulating the interaction between supra-thermal particles and the magnetic field in astrophysical shocks
复制标题
模拟天体物理冲击中超热粒子与磁场之间的相互作用
DOI：
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
A. Marcowith
中科院分区：
文献类型：
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作者：
A. J. van Marle;F. Casse;A. Marcowith
为了对天体物理激波中发生的磁场放大和粒子加速进行建模，我们需要一个能够有效地对激波的大尺度结构进行建模的程序，同时仍然考虑超热粒子的动力学方面。从成熟的MPI-AMRVAC磁流体程序出发，我们创建了一个程序，它结合了超热粒子的粒子在单元(PIC)方法的动力学处理和基于网格的流体动力学(MHD)的大规模效率来模拟热等离子体，包括使用自适应网格加密。使用这个程序，我们模拟天体物理激波，改变马赫数和磁场与激波之间的角度，以对照现有结果测试我们的程序，并研究激波的演化和超热粒子的行为。我们发现，结合PIC-MHD方法可以准确地恢复以前用纯PIC码得到的结果。此外，与以前的工作相比，代码的效率允许我们在更大程度上探索可用的参数空间。我们的结果表明，当磁场与流动方向成大角度时，在近斜激波中可以发生有效的粒子加速。
In order to model the magnetic field amplification and particle acceleration that takes place in astrophysical shocks, we need a code that can efficiently model the large-scale structure of the shock, while still taking the kinetic aspect of supra-thermal particles into account. Starting from the proven MPI-AMRVAC magnetohydrodynamics code we have created a code that combines the kinetic treatment of the Particle-in-Cell (PIC) method for suprathermal particles with the large-scale efficiency of grid-based hydrodynamics (MHD) to model the thermal plasma, including the use of adaptive mesh refinement. Using this code we simulate astrophysical shocks, varying both the Mach-number and the angle between the magnetic field and the shock to test our code against existing results and study both the evolution of the shock and the behaviour of supra-thermal particles. We find that the combined PIC-MHD method can accurately recover the results that were previously obtained with pure PIC codes. Furthermore, the efficiency of the code allows us to explore the available parameter space to a larger degree than has been done in previous work. Our results suggest that efficient particle acceleration can take place in near-oblique shocks were the magnetic field makes a large angle with the direction of the flow.
存在有效宇宙射线加速时激波前兆的普遍行为
影响因子：
4.8
作者：
Reville B
通讯作者：
Reville B