| Project/Area Number |
06640497
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
物性一般(含基礎論)
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
TSUBOTA Makoto Tohoku University Institute of Fluid Science Assoc.Prof., 流体科学研究所, 助教授 (10197759)
|
|---|
| Project Period (FY) |
1994 – 1995
|
| Project Status |
Completed (Fiscal Year 1995)
|
| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1995: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1994: ¥1,600,000 (Direct Cost: ¥1,600,000)
|
|---|
| Keywords | Superfluid / Quantized Vortex / Computational Physics / Low Temperature / Pinning / Vortex Array / ピン止め / ソリトン / 超流動ヘリウム / 熱カウンター流 / 再結合 |
|---|
| Research Abstract |
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.
|
