Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom.
Phys Rev Lett. 2010 Jul 30;105(5):055004. doi: 10.1103/PhysRevLett.105.055004.
Generation of Alfvénic (magnetohydrodynamic) vortices by the interaction of compressible plasma flows with magnetic-field-aligned blunt obstacles is modeled in terms of magnetohydrodynamics. It is found that periodic shedding of vortices with opposite vorticity is a robust feature of the interaction in a broad range of plasma parameters: for plasma beta from 0.025 to 0.5, and for the flow speeds from 0.1 to 0.99 of the fast magnetoacoustic speed. The Strouhal number is the dimensionless ratio of the blunt body diameter to the product of the period of vortex shedding and the inflow speed. It is found to be consistently in the range 0.15-0.25 in the whole range of parameters. The induced Alfvénic vortices are compressible and contain spiral-armed perturbations of the magnetic field strength and plasma mass density up to 50%-60% of the background values. The generated electric current also has the spiral-armed structuring.
采用磁流体力学方法对可压缩等离子体流与磁场定向钝体相互作用产生的阿尔芬（磁流体动力学）涡旋进行建模。结果表明，在较宽的等离子体参数范围内，周期性地产生具有相反旋度的涡旋是相互作用的一个稳定特征：对于等离子体β从 0.025 到 0.5，以及对于速度从 0.1 到 0.99 的快磁声速。斯特劳哈尔数是钝体直径与涡旋脱落周期和流入速度乘积的无量纲比。在整个参数范围内，它一直保持在 0.15-0.25 的范围内。感应的阿尔芬涡旋是可压缩的，并包含磁场强度和等离子体质量密度的螺旋臂扰动，达到背景值的 50%-60%。产生的电流也具有螺旋臂结构。
