Development of the multi-fluid transport code on the tokamak flux coordinates

トカマク磁気座標における多流体輸送コードの開発

本多 充; 福山 淳*

Honda, Mitsuru; Fukuyama, Atsushi*

The one-dimensional multi-fluid transport code TASK/TX has been developed for investigating the physics in tokamaks regarding rotation, the radial electric field , transient phenomena and so on. Compared to diffusive transport equations, its equation system is more fundamental in that it is based on the so-called two-fluid equation system that consists of the equations of motion together with Maxwell's equations. For example, in TASK/TX, an explicit quasi-neutrality condition is not thus required. Highly consistency of the system enables us to reproduce the torque and the concomitant generation of by itself. TASK/TX has originally built on the cylindrical coordinates for the sake of simplicity and thus no geometrical factors enter. The original set of equations is sufficient to qualitatively investigate the physics, but it is hardly applied to actual tokamak plasmas due to their shaping. From the physics point of view, the Pfirsch-Schlter enhancement of the dielectric constant of a plasma cannot be expressed, for example. Recently we have derived the set of governing equations on the tokamak flux coordinates in a manner consistent with the current TASK/TX concept. The set of equations are renewed to be more suited to the actual numerical implementation and are implemented in TASK/TX. Coupling of TASK/TX and an equilibrium solver makes it possible to carry out time-dependent simulations in actual tokamaks.