Numerical simulations of Z-pinch experiments to create supersonic differentially-rotating plasma flows
Numerical simulations of Z-pinch experiments to create supersonic differentially-rotating plasma flows
复制标题
用于产生超音速差速旋转等离子体流的 Z 箍缩实验的数值模拟
DOI：
10.1016/j.hedp.2012.12.001
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发表时间：
2013
影响因子：
1.6
通讯作者：
Bocchi M
中科院分区：
文献类型：
--
作者：
Bocchi M
吸积盘的物理学对于理解包括原恒星、X射线双星和活动星系核在内的各种天体物理源具有根本的重要性。流体动力学流动和磁场之间的相互作用以及产生不稳定性的可能性是一个积极研究的主题，如果能得到专门实验研究的支持，将受益匪浅。这种努力是在他们的起步阶段，但在努力推动企业前进，我们提出了一个实验配置，采用了修改后的圆柱形线阵列Z箍缩产生旋转等离子体流相关的吸积盘。我们提出了三维电阻磁流体动力学模拟，展示了这种方法可以实现。在模拟中，形成了一个旋转的等离子体圆柱或环，典型的旋转速度为30 km s-1，马赫数为104，雷诺数超过107。等离子体也在差动旋转。不同的外部磁场配置的实施进行了讨论。结果发现，一个适度的均匀的垂直场的1 T可以影响系统的动力学，可以用来研究磁场夹带和放大通过差分旋转。偶极场可能相关的吸积柱的研究也被认为是。
The physics of accretion disks is of fundamental importance for understanding of a wide variety of astrophysical sources that includes protostars, X-ray binaries, and active galactic nuclei. The interplay between hydrodynamic flows and magnetic fields and the potential for turbulence-producing instabilities is a topic of active research that would benefit from the support of dedicated experimental studies. Such efforts are in their infancy, but in an effort to push the enterprise forward we propose an experimental configuration which employs a modified cylindrical wire array Z-pinch to produce a rotating plasma flow relevant to accretion disks. We present three-dimensional resistive magnetohydrodynamic simulations which show how this approach can be implemented. In the simulations, a rotating plasma cylinder or ring is formed, with typical rotation velocity∼ 30 km s− 1, Mach number∼ 4, and Reynolds number in excess of 10 7. The plasma is also differentially rotating. Implementation of different external magnetic field configurations is discussed. It is found that a modest uniform vertical field of 1 T can affect the dynamics of the system and could be used to study magnetic field entrainment and amplification through differential rotation. A dipolar field potentially relevant to the study of accretion columns is also considered.