| Co-Investigator(Kenkyū-buntansha) |
MOHRI Akihiro KYOTO UNIVERSITY, Professor Emeritus, 総合人間学部, 名誉教授 (10025926)
MICHISHITA Toshinori Fac. of Integrated Human Studies, KYOTO UNIVERSITY Research Associate, 総合人間学部, 助手 (00166050)
YUYAMA Tetsumori Fac. of Integrated Human Studies, KYOTO UNIVERSITY Research Associate, 総合人間学部, 助手 (90026815)
ISHIGURO Seiji Natl.Inst.Fusion Science, Associate Professor, 助教授 (10193301)
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| Research Abstract |
With a newly developed emitter array of 19 cathodes for producing electron strings with 1mm in diam. and 230mm in length, we have successfully produced various shapes of electron density distribution, discrete and/ or continuous. An interesting feature of 2-dimensional dynamics of axially homogeneous electron strings is that the system dynamics is equivalent to incompressible Euler fluid and the electron density is proportional to the vorticity. Combining the dynamics control with a high-resolution and high-sensitivity imaging technique, we have achieved several findings on the vortex dynamics.
(a) Dynamics of the discrete electron strings follows the Hamiltonian description of the vortex string system. [J.Phys.Soc.Jpn.Lett.Vol.68 (1999) 3766.]
(b) A low level of the background vorticity accelerates merging between vortex strings.[ibid.]
(c) A vortex string moves up the gradient of the background vortex distribution. [6]
(d) A series of crystal states of discrete vortex arrays appear in the relaxation process of the initially 19 strings that show stochastic motions and inelastic collisions.[1,2,4, to be published.]
(e) Patches and rings of depleted zone (holes) in the background vortex distribution have strong influences on the dynamics of eminent vortex strings and on the process of crystallization.[1,2,4, to be published.]
(f) The vorticity is found experimentally to be functionally expressed in terms of the stream function as the system approaches to the equilibrium state.[3, to be published.]
(g) Many statistical variables, including energy, angular momentum, circulation, enstrophy, entropy etc., are obtained from the experimental data and given as a function of time along relaxation.
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