189 research outputs found
Reading Japanese Documents from the Marega Collection: An Introductory Manual with Selected Texts
No full textThe volume, authored by Naohiro Ōta, and edited by Silvio Vita, Chiara Ghidini, and Luca Milasi, introduces the Mario Marega (1902-1978) collection of manuscripts at the Vatican Library. The complete collection comprises over 14,000 documents from Kyushu spanning the 17th-20th centuries recently cataloged and digitized and available through NIJL. The manual details a selection of documents specifically selected for the purpose of learning to read, transcribe, and translate komonjo. The book comprises an introduction, followed by, chapter 1, which includes four explanatory essays: “Documents as Material Objects,” “The Texts: Cursive Script and Language,” “The Historical Context of the Marega Documents,” and “Reference Tools and Suggested Readings.” The next two chapters cover “Reading Models” and “Texts for Practice.” Several appendices include information helpful to understanding komonjo, especially the documents related to Christianity in the Marega Collection. The author and editors compiled the volume mainly as a useful resource for students of sōrōbun and komonjo, and with the hope to provide up-to-date information about Japanese paleography and diplomatics of the Pre- and Early Modern period which will prove of interest for more advanced specialists, also
Research of turbulent transport due to dissipative trapped electron mode in tokamak plasmas
No full textORCID 0000-0002-0712-8811The purpose of this article is to study turbulent transport for laboratory plasmas in toroidal devices by gyrokinetic analyses. Linear analysis is performed to clarify the dominant mode for tokamak plasmas. The dissipative trapped electron mode (d-TEM) and the ion temperature gradient (ITG) mode are predicted using the Sugama collision model operator [Sugama et al., Phys. Plasmas 16, 112503 (2009)]. Nonlinear gyrokinetic analysis is used to quantify turbulent transport. The nonlinear simulation results show the levels of particle and energy transport, where the d-TEM and ITG mode are unstable. The effect of zonal flows is studied by the linear and nonlinear simulation results. The results of the analysis are compared when two types of model collision operator, which are the Sugama and Lenard–Bernstein [Phys. Rev. 112, 1456 (1958)] collision model operators, are used. In this study, the simulation results using the Sugama collision operator show a stronger effect of the zonal flows on the turbulent transport than those using the Lenard–Bernstein collision operator, as predicted by the linear simulation result such as the zonal flow decay time.journal articl
Multi-Dimensional Structure of the Electric Field in Tokamak H-Mode
No full textIn tokamak H-mode, a large poloidal flow exists in an edge transport barrier, and the electrostatic potential and density profiles can be steep both in the radial and poloidal direction. Two-dimensional structures of the potential, density and flow velocity near the edge of a tokamak plasma are investigated. The model includes the nonlinearity in bulk-ion viscosity and turbulence-driven shear viscosity. For the case with a strong radial electric field (H-mode), a two-dimensional structure in a transport barrier is obtained, giving a poloidal shock with a solitary radial electric field profile. The poloidal electric field induces convective transport in the radial direction, and poloidal asymmetry makes the flux-surface-averaged particle flux direct inward with a pinch velocity on the order of 1 [m/s]. A large poloidal flow with radial shear enhances the inward pinch velocity. The abrupt increase of this inward ion and electron flux at the onset of L-to-H-mode transition explains the rapid establishment of the density pedestal at the transition.journal articl
Two-Dimensional Model Including the Mechanism of a Poloidal Shock Structure and Geodesic Acoustic Mode in Toroidal Plasmas
No full textIn H-mode plasmas, two-dimensional steep structures of the electrostatic potential and density are formed when a large poloidal flow exists, whose formation mechanism has been studied to obtain a quantitative understanding of the particle transport in H-mode transport barriers. The previous two-dimensional model is extended to investigate parallel flow dynamics when potential and density distributions do not satisfy the Boltzmann relation. The extended model includes the generation mechanism of a poloidal shock structure and geodesic acoustic mode, whose competitive formation can be studied.journal articl
Two-Dimensional Structure and Particle Pinch in Tokamak H Mode
No full textTwo-dimensional structures of the electrostatic potential, density, and flow velocity near the edge of a tokamak plasma are investigated. The model includes the nonlinearity in bulk-ion viscosity and turbulence-driven shear viscosity. For the case with the strong radial electric field (H mode), a two-dimensional structure in a transport barrier is obtained, giving a poloidal shock with a solitary radial electric field profile. The inward particle pinch is induced from this poloidal asymmetric electric field, and increases as the radial electric field becomes stronger. The abrupt increase of this inward ion and electron flux at the onset of L- to H-mode transition explains the rapid establishment of the density pedestal, which is responsible for the observed spontaneous self-reorganization into an improved confinement regime.journal articl
Radially Distributed Instabilities and Nonlinear Process to Generate Pressure Variation in a Torus Plasma
No full text
Two-Dimensional Model Including the Mechanism of a Poloidal Shock Structure and Geodesic Acoustic Mode in Toroidal Plasmas
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