Quasiparticle-scattering measurements of laminar and turbulent vortex flow in the spin-down of superfluid 3He-B
Quasiparticle-scattering measurements of laminar and turbulent vortex flow in the spin-down of superfluid 3He-B
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超流体 3He-B 旋转下降过程中层流和湍流涡流的准粒子散射测量
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发表时间：
2012
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通讯作者：
J. Makinen
中科院分区：
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作者：
J. Hosio;V. Eltsov;M. Krusius;J. Makinen
本文研究了超流3 He-B中快速停止旋转后量子化涡旋的动力学。我们使用Andreev反射的热激发监测涡旋运动与石英音叉振荡器在两个不同的实验设置在0.2Tc以下的温度。在流动环境中偏离理想的圆柱对称性会导致早期的衰变变成湍流。这是从涡旋密度在自旋下降之前的值之上的快速初始过冲及其随后的具有t^（-3/2）时间依赖性的衰减来识别的。高极化的漩涡沿着旋转轴显着抑制有效湍流运动粘度低于更均匀的湍流的值，并导致层流后期响应。从极化涡位形的进动频率可以确定T < 0.15Tc时的涡耗散。在消失的正常组件密度的限制，层流耗散被发现接近温度无关的值，其起源目前正在讨论中。
The dynamics of quantized vortices is studied in superfluid 3He-B after a rapid stop of rotation. We use Andreev reflection of thermal excitations to monitor vortex motion with quartz tuning fork oscillators in two different experimental setups at temperatures below 0.2Tc. Deviations from ideal cylindrical symmetry in the flow environment cause the early decay to become turbulent. This is identified from a rapid initial overshoot in the vortex density above the value before the spin-down and its subsequent decay with a t^(-3/2) time dependence. The high polarization of the vortices along the rotation axis significantly suppresses the effective turbulent kinematic viscosity below the values reported for more homogeneous turbulence and leads to a laminar late-time response. The vortex dissipation down to T < 0.15Tc is determined from the precession frequency of the polarized vortex configuration. In the limit of vanishing normal component density, the laminar dissipation is found to approach a temperature-independent value, whose origin is currently under discussion.