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Three-dimensional Dynamics of Quan

拳的三维动力学

基本信息

批准号：
06640497
负责人：
TSUBOTA Makoto
金额：
$ 1.34万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

We have studied three-dimensional dynamics of quantized vortices in superfluid helium. First, we investigated vortex pinning that simulates the roughness of the channel surface. After the condition that vortices are attracted to a pinning site is discussed, the capacity of a pinning site is studied ; a pinning site can keep only less than five vortices. The obtained critical depinning velocities are compared with some experimental results for thermal counterflow. Secondly, vortex dynamics in rotating superfluid is studied. A rotating superfluid is known to form an array of vortices which are paralled to the rotational axis, yet very little is understood about the dynamics. Thus we made two-dimensional analysis, studying the formation of vortex arrays and its decay in spin-down processes which are typical of dynamical problems. However, only two-dimensional analysis is insufficient to understand the real system. Hence three-dimensional analysis was made. The numerical calculation for a superfluid in a rotating spherical vessel found that the angular velocity of the vessel necessary for stretching a small vortex nucleated at the boundary is larger than the observed critical angular velocity for one-vortex nucleation ; not a nucleated vortex but some remnant vortices may play an important role in a real system. The array decay through the spin-down processes is studied in detail. The propagation of a soliton along a vortex is investigated.

我们研究了超流氦中量子化涡旋的三维动力学。首先，我们研究了模拟通道表面粗糙度的涡钉扎。在讨论了涡被吸引到钉扎位置的条件后，研究了钉扎位置的容纳能力，一个钉扎位置只能容纳少于5个涡。得到的临界脱钉速度与热逆流的一些实验结果进行了比较。其次，研究了旋转超流中的涡旋动力学。已知旋转的超流体会形成一系列平行于旋转轴的涡旋，但对动力学的了解很少。因此，我们进行了二维分析，研究了涡旋阵列的形成和衰减的自旋下降过程中，这是典型的动力学问题。然而，仅仅二维分析不足以理解真实的系统。因此，进行了三维分析。通过对旋转球形容器中超流体的数值计算发现，在边界处形成小涡所需的容器角速度大于观察到的单涡成核的临界角速度，在真实的系统中起重要作用的可能不是成核涡，而是一些残余涡.通过自旋下降过程的阵列衰减进行了详细研究。研究了孤子沿着涡旋的传播。