Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Idomura, Yasuhiro; Kishimoto, Yasuaki; Tokuda, Shinji
Europhysics Conference Abstracts (CD-ROM), 29C, 4 Pages, 2005/00
A gyrokinetic simulation is an essential tool to study anomalous turbulent transport in tokamak plasmas. Although a delta-f PIC code or a particle approach has been a standard method, it has difficulty in implementing non-conservative effects such as a heat source and collisions, which are important for a realistic long time turbulence simulation. On the other hand, a Vlasov code or a mesh approach is much more flexible to simulate these non-conservative effects. In this work, a new gyrokinetic Vlasov code is developed based on the CIP method, which is one of recent advanced CFD schemes. Numerical properties and computational costs of the gyrokinetic PIC and CIP codes are compared in ITG turbulence simulations.
Miyato, Naoaki; Kishimoto, Yasuaki; Li, J.
JAERI-Research 2004-010, 18 Pages, 2004/08
JAERI-Research-2004-010.pdf:4.55MB
Global structure of zonal flows driven by ion temperature gradient driven turbulence in tokamak plasmas is investigated using a global electromagnetic Landau fluid code. Characteristics of the coupled system of the zonal flows and the turbulence change with the safety factor 
. In a low region stationary zonal flows are excited and suppress the turbulence effectively. Coupling between zonal flows and poloidally asymmetric pressure perturbations via a geodesic curvature makes the zonal flows oscillatory in a high region. Also we identify energy transfer from the zonal flows to the turbulence via the poloidally asymmetric pressure perturbations in the high region. Therefore in the high region the zonal flows cannot quench the turbulet transport completely.
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.