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Watanabe, Tsutomu*; Takagi, Marie*; Shimoyama, Ko*; Kawashima, Masayuki*; Onodera, Naoyuki; Inagaki, Atsushi*
Boundary-Layer Meteorology, 181(1), p.39 - 71, 2021/10
Times Cited Count：6 Percentile：45.38(Meteorology & Atmospheric Sciences)A double-distribution-function lattice Boltzmann model for large-eddy simulations of a passive scalar field is described within and above a plant canopy. For a top-down scalar, for which the plant canopy serves as a distributed sink, the flux of the scalar near the canopy top are predominantly determined by sweep motions originating far above the canopy. By contrast, scalar ejection events are induced by coherent eddies generated near the canopy top. In this paper, the generation of such eddies is triggered by the downward approach of massive sweep motions to existing wide regions of weak ejective motions from inside to above the canopy.
Miyato, Naoaki; Kishimoto, Yasuaki; Li, J.*
Plasma Physics and Controlled Fusion, 48(5A), p.A335 - A340, 2006/05
Times Cited Count：26 Percentile：64.63(Physics, Fluids & Plasmas)It is well known that drift wave turbulence such as ion temperature gradient (ITG) driven turbulence and zonal flows nonlinearly generated from it play an important role in anomalous transport in tokamak plasmas. The zonal flows can regulate turbulent transport and trigger formation of transport barriers. In toroidal plasmas there are two kinds of zonal flows. One is stationary zonal flow which is dominant in a low safety factor (
) region. The other is oscillatory ones appearing in a high region. Global ITG turbulence simulations have shown that the frequencies of the oscillatory zonal flows do not vary continuously with a radius, but the oscillatory zonal flows have the same frequency over a certain radial region. It is considered that the nonlocal behaviour becomes weak for small 
, where 
is an ion Larmor radius and 
is a minor radius of a torus. In this research effects of on the nonlocal behaviour of the zonal flows are investigated by global Landau fluid ITG simulations.
Takizuka, Tomonori; Hojo, Hitoshi*; Hatori, Tadatsugu*
Purazuma, Kaku Yugo Gakkai-Shi, 78(9), p.857 - 912, 2002/09
Transport along field lines in magnetic confinement plasmas is reviewed. Collisionless and collisional-diffusive transports are discussed. Because of their fast transport, features of plasmas along field lines are apt to behave nonlocally. A nonlocal phenomenon of scrape-off layer (SOL) and divertor plasmas in a tokamak is introduced, whose asymmetry along field lines is induced by the thermoelectric instability related to the SOL current. A local phenomenon called MARFE can be brought by the strong radiation cooling. The "snake" with nonlocal feature along field lines but with local structure perpendicular to the field is observed in a tokamak core plasma. For mirror-confined plasmas, axial particle losses from the mirror ends, especially pitch-angle-sattering losses into the loss cone and nondiabatic losses due to the breakdown of adiabaticity of the magnetic moment, are also discussed in the relation to nonlocal axial transport.
Kishimoto, Yasuaki
Purazuma, Kaku Yugo Gakkai-Shi, 78(9), p.857 - 860, 2002/09
In order to understand the various phenomena related to the nonlocal transport and structure formation in the plasma, we reviw the topics in the field of (1)laser implosion plasma, (2)space plasma, and (3) magnetic fusion plasma, as a spatial series.
Progress of Theoretical Physics, 59(4), p.1085 - 1100, 1978/04
Times Cited Count：12no abstracts in English
