Masanori Nunami

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One of the the basic assumptions in perturbative renormalization as a physical concept in a trivial, perturbatively renormalizable theory is that the intrinsic cutoff of the theory is so large that the nonperturbative effects due to the finite intrinsic cutoff become very small in the infrared regime. We treat trivial theories, including unrenormalizable(More)
With the prevalence of massively parallel computer architecture, MPI parallelization of existing simulation codes for stand-alone system and its parallel optimization to achieve feasible scalability are in critical need. Of many numerical approaches, adaptive mesh refinement(AMR) is known to be one of the particular cases in which MPI parallelization is(More)
The driving and damping mechanism of plasma flow is an important issue because flow shear has a significant impact on turbulence in a plasma, which determines the transport in the magnetized plasma. Here we report clear evidence of the flow damping due to stochastization of the magnetic field. Abrupt damping of the toroidal flow associated with a transition(More)
A plasma turbulence research based on 5D gyrokinetic simulations is one of the most critical and demanding issues in fusion science. To pioneer new physics regimes both in problem sizes and in time scales, an improvement of strong scaling is essential. Overlap of computations and communications is a promising approach in improving strong scaling, but it(More)
A numerical scheme for interface between different hierarchy levels with different grid sizes and time step intervals is designed for a full particle-in-cell simulation code with adaptive mesh refinement technique. Physical information in the interface region is exchanged recursively over all hierarchy levels. The exchange processes are performed at the(More)