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Miyato, Naoaki; Li, J. Q.*; Kishimoto, Yasuaki
Nuclear Fusion, 45(6), p.425 - 430, 2005/06
Times Cited Count:25 Percentile:61.97(Physics, Fluids & Plasmas)Using a global Landau fluid code in toroidal geometry, an electromagnetic ion temperature gradient (ITG) driven turbulence-zonal mode system is investigated. Two different types of zonal flows, i.e. stationary zonal flows in a low (safety factor) region and oscillatory ones in a high region which are called geodesic acoustic modes (GAM), are found to be simultaneously excited in a torus. The stationary flows efficiently suppress turbulent transport, while the oscillatory ones weakly affect the turbulence due to their time varying nature. Therefore in the low region where the zonal flows are almost stationary, the zonal flows are dominant over the turbulence. On the other hand, the turbulence is still active in the high region where the zonal flows are oscillatory.
Miyato, Naoaki; Li, J.*; Kishimoto, Yasuaki
Journal of Plasma and Fusion Research SERIES, Vol.6, p.581 - 584, 2004/00
Electromagnetic effect on ion temperature gradient driven turbulence and zonal flow generated from the turbulence is investigated based on global electromagnetic Landau fluid simulations in tokamak plasmas. Turbulent transport decreases by increasing beta in a low beta regime. Two types of zonal flow are observed. One is almost stationary flow formed in a low safety factor (q) region, which is weaker at higher beta. The other is flow oscillating coherently at the geodesic acoustic mode (GAM) frequency.
Li, J.; Kishimoto, Yasuaki
Physical Review Letters, 89(11), p.115002_1 - 115002_4, 2002/09
Times Cited Count:31 Percentile:77.34(Physics, Multidisciplinary)Interaction between small-scale zonal flows and large-scale turbulence is investigated. The key mechanism is identified as radially non-local mode coupling. Fluctuating energy can be non-locally transferred from the unstable longer to stable or damped shorter wavelength region, so that turbulence spectrum is seriously deformed and deviated from the nonlinear power law structure. Three-dimensional gyro-fluid ion temperature gradient (ITG) turbulence simulations show that an ion transport bursting behavior is consistently linked to the spectral deformity with the causal role of ITG-generated zonal flows in tokamak plasmas.
Yamagiwa, Mitsuru; Hirose, A*; Elia, M.*
PPL-163, 22 Pages, 1997/01
no abstracts in English
Yamagiwa, Mitsuru; Hirose, A*; Elia, M.*
Plasma Physics and Controlled Fusion, 39(3), p.531 - 540, 1997/00
Times Cited Count:6 Percentile:24.41(Physics, Fluids & Plasmas)no abstracts in English
J.Y.Kim*; Kishimoto, Yasuaki; Wakatani, Masahiro*; Tajima, Toshiki*
Physics of Plasmas, 3(10), p.3689 - 3695, 1996/10
Times Cited Count:52 Percentile:82.11(Physics, Fluids & Plasmas)no abstracts in English
Kishimoto, Yasuaki; Tajima, Toshiki*; W.Horton*; LeBrun, M. J.*; J.Y.Kim*
Physics of Plasmas, 3(4), p.1289 - 1307, 1996/04
Times Cited Count:79 Percentile:89.55(Physics, Fluids & Plasmas)no abstracts in English