Comparison of confinement physiscs for toroidal plasmas

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1. Virtual reality display system was developed as an advanced visualization method to understand complex phenomena in fusion plasmas by using computer simulation. In particular, interfaces between the display system and human beings have been developed, and we have realized a method to analyze conveniently and efficiently computation results in interactive way in the virtual reality space. 2. Three dimensional nonlinear MHD simulation on spherical tokamak dynamics was executed to obtain occurrence of global relaxation phenomena, starting from an initial state based on an actual experimental observation. After a process of pressure collapse, the torus returns to a state close to the axisymmetric initial configuration but with a broader pressure profile. 3. The three dimensional equilibrium code HINT, which does not assume the existence of nested magnetic surfaces, was modified to extend functions. 4. A new MHD simulation code for a full three dimensional geometry of helical plasmas were developed and applied for nonlinear growth of unstable modes in the LHD configuration. A relaxation phenomenon driven by pressure driven instabilities was observed, which was not destructive but caused transition to a new equilibrium. 5. A modeling was made to describe basic dynamics of the anomalous transport phenomena. Incorrect mathematical treatment of singularity in previous modeling by other authors was indicated and a new modeling was proposed. 6. Experiments of helical plasmas were executed to study fluctuations in periphery plasmas and improvement of confinement. A reversal of particle flux from outward to inward was found.