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)
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)
One of the important phenomena in magnetically-confined fusion plasma is plasma turbulence, which causes particle and heat transport and degrades plasma confinement. To address multi-scale turbulence including temporal and spatial scales of electrons and ions, we extend our gyrokinetic Vlasov simulation code GKV to run efficiently on peta-scale(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)
Unrenormalizable theories contain infinitely many free parameters. Considering these theories in terms of the Wilsonian renormalization group (RG), we suggest a method for removing this large ambiguity. Our basic assumption is the existence of the maximal ultraviolet cutoff in a cutoff theory, and we require that the theory be so fine-tuned as to reach the(More)