| Budget Amount *help |
¥19,760,000 (Direct Cost: ¥15,200,000、Indirect Cost: ¥4,560,000)
Fiscal Year 2014: ¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
Fiscal Year 2013: ¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
Fiscal Year 2012: ¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2011: ¥8,060,000 (Direct Cost: ¥6,200,000、Indirect Cost: ¥1,860,000)
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| Outline of Final Research Achievements |
We report the results obtained in the present study as follows, for the purpose of investigating vortex motions in superfluid helium by using novel characteristics of a quantized vortex.
(1) Quantized vortex rings can be produced by vibrating motions of an object immersed in superfluid helium, emitting in random directions. (2) The diameters of vortex rings, estimated from the velocities of the rings, are distributed from 0.2 to 1 micro meter, suggesting that vortex rings cascade to smaller rings by reconnection between vortices. (3) Vortex rings are emitted radially from a point source. (4) The diameters of vortex rings are limited to sizes smaller than a vibrating amplitude of an object. (5) Simulations of vortex emissions by an oscillating sphere reveal that vortex rings are emitted anisotropically in directions. (6) The direct measurements of vortex wave spectrums require new methods of attaching vortices between a vibrating object and a probe.
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