Search Results 1-20 of 328

  • The Eulerian variational formulation of the gyrokinetic system in general spatial coordinates

    SUGAMA Hideo , MATSUOKA Keisuke , NUNAMI Masanori , SATAKE Shinsuke

    … In the present study, the variation of the Lagrangian density with respect to the metric tensor is taken to directly obtain the symmetric pressure tensor, which includes the effect of turbulence on the momentum transport. … The results obtained here are considered useful for global gyrokinetic simulations investigating both neoclassical and turbulent transport processes even in general non-axisymmetric toroidal systems. …

    Physics of Plasmas (28), 022312, 2021-02-18

    IR 

  • Simultaneous Observation of Silicon and Boron Impurity Behaviors in the Core Region of a Mid-Density LHD Plasma

    TAMURA Naoki , YOSHINUMA Mikirou , IDA Katsumi , SUZUKI Chihiro , GOTO Motoshi , OISHI Tetsutarou , SHOJI Mamoru , MUKAI Kiyofumi , FUNABA Hisamichi

    <p>Line emissions from both silicon (Si) and boron (B) impurity ions introduced by a single tracer-encapsulated solid pellet (TESPEL) containing silicon hexaboride (SiB<sub>6</sub>) …

    Plasma and Fusion Research 16(0), 1202094-1202094, 2021

    J-STAGE 

  • Effect of the Pitch Modulation of Helical Coils on the Core Plasma Performance of the LHD-Type Helical Fusion Reactor

    GOTO Takuya , ICHIGUCHI Katsuji , TAMURA Hitoshi , MIYAZAWA Junichi , SATAKE Shinsuke , YAMAGUCHI Hiroyuki , YANAGI Nagato , the FFHR Design Group

    … The analysis of the MHD stability and neoclassical transport for the pitch modulation <i>α</i> … It was found that the MHD stability is clearly improved without deteriorating the energy transport property by changing the pitch modulation <i>α</i> …

    Plasma and Fusion Research 16(0), 1405085-1405085, 2021

    J-STAGE 

  • Benchmark of a new multi-ion-species collision operator for δf Monte Carlo neoclassical simulation  [in Japanese]

    SATAKE Shinsuke , Nakata Motoki , Pianpanit Theerasarn , SUGAMA Hideo , NUNAMI Masanori , MATSUOKA Seikichi , Ishiguro Seiji , KANNO Ryutaro

    … A numerical method to implement a linearized Coulomb collision operator in the two-weight Monte Carlo method for multi-ion-species neoclassical transport simulation is developed. …

    Computer Physics Communications (252), 107249, 2020-03-02

    IR 

  • Extended investigations of isotope effects on ECRH plasma in LHD

    TANAKA Kenji , Nakata Motoki , Ohtani Yoshiaki , TOKUZAWA Tokihiko , YAMADA H. , Warmer Felix , NUNAMI Masanori , SATAKE Shinsuke , Tala T. , Tsujimura Ii Toru , TAKEMURA Yuki , Kinoshita T. , TAKAHASHI Hiromi , YOKOYAMA Masayuki , SEKI Ryosuke , IGAMI Hiroe , YOSHIMURA Yasuo , KUBO Shin , SHIMOZUMA Takashi , AKIYAMA Tsuyoshi , YAMADA Ichihiro , YASUHARA Ryo , FUNABA Hisamichi , YOSHINUMA Mikiro , IDA Katsumi , GOTO Motoshi , SHOJI Mamoru , MASUZAKI Suguru , MICHAEL Clive A. , Vacheslavov L.N. , OSAKABE Masaki , LHD Experiment Group

    … A clear difference of transport and turbulence characteristics in H and D plasmas was found in the core region, with normalized radius ρ < … On the other hand, differences of transport and turbulence were relatively small in low collisionality regime. … Power balance analysis and neoclassical calculation showed a reduction of the anomalous contribution to electron and ion transport in D plasma compared with H plasma in the high collisionality regime. …

    Plasma Physics and Controlled Fusion 62(2), 024006, 2019-12-16

    IR 

  • Improved linearized model collision operator for the highly collisional regime

    SUGAMA Hideo , MATSUOKA Keisuke , SATAKE Shinsuke , NUNAMI Masanori , Watanabe T.-H.

    … The improved linearized model operator retains the conservation laws of particles, momentum, and energy, and it reproduces the same friction-flow relations as derived by the linearized Landau operator so that this model can be used to correctly evaluate neoclassical transport fluxes in all collisionality regimes. … In addition, for application to gyrokinetic simulations of turbulent transport, the improved operator is transformed into the gyrophaseaveraged form by keeping the finite gyroradius effect. …

    Physics of Plasmas (26), 102108, 2019-10-11

    IR 

  • Asymmetry of parallel flow on the Large Helical Device

    Chen Jun , IDA Katsumi , YOSHINUMA Mikiro , KOBAYASHI Tatsuya , MURAKAMI Sadayoshi , YAMAMOTO Yasuhiro , Ye M.Y , Lyu B

    … An asymmetric parallel return flow, which modifies the parallel component of the flow, is expected to meet the zero divergence of the flow on a flux surface based on the common neoclassical theory for torus plasma. … One possible explanation for this variation could be radial transport due to anomalous perpendicular viscosity as well as strongly poloidally asymmetric radial flow. …

    Nuclear Fusion 59(10), 106036, 2019-09-04

    IR 

  • Consideration of the Influence of Coil Misalignment on the Chinese First Quasi-Axisymmetric Stellarator Magnetic Configuration

    SHIMIZU Akihiro , XIONG Guozhen , XU Yuhong , LIU Hai , ZHANG Xin , HUANG Jie , WANG Xianqu , TANG Changjian , YIN Dapeng , WAN Yi , CFQS Team , LIU Haifeng , KINOSHITA Shigeyoshi , ISOBE Mitsutaka , OKAMURA Shoichi , OGAWA Kunihiro , NAKATA Motoki , SATAKE Shinsuke , SUZUKI Chihiro

    … Calculation results show that if the magnitude of displacement is less than 10 mm, the effects on these physical properties are small, and the good neoclassical transport property is retained.</p> …

    Plasma and Fusion Research 14(0), 3403151-3403151, 2019

    J-STAGE 

  • Comparisons of the Plasma Performance of Future Thailand Tokamak using Various External Heating Schemes

    BUARUK Suphachok , MAKMOOL Thanaphan , PROMPING Jiraporn , ONJUN Thawatchai , SANGAROON Siriyaporn , WISITSORASAK Apiwat , GARCIA Jeronimo , CHATTHONG Boonyarit

    … The code consists of a 1D transport solver with general 2D magnetic equilibria, and includes several heat, particle and impurities transport models as well as heat, particle and momentum sources. … In this work, a combination of a mixed Bohm/gyro-Bohm anomalous transport model and an NCLASS neoclassical transport model are used to calculate plasma core diffusivities. …

    Plasma and Fusion Research 14(0), 3403153-3403153, 2019

    J-STAGE 

  • Global Effects on the Variation of Ion Density and Electrostatic Potential on the Flux Surface in Helical Plasmas

    FUJITA Keiji , SATAKE Shinsuke , KANNO Ryutaro , NUNAMI Masanori , NAKATA Motoki , GARCÍA-REGAÑA José Manuel

    … <p>Since the observation of impurity hole in LHD, which contradicts the prediction of the conventional neoclassical transport theory, several attempts have been made to explain the mechanism behind the phenomenon. … Here, a global neoclassical simulation code FORTEC-3D is applied to evaluate Φ<sub>1</sub>, including the global effects, for the first time. …

    Plasma and Fusion Research 14(0), 3403102-3403102, 2019

    J-STAGE 

  • Recent Progress in the Numerical Simulation Reactor Research Project

    SUGAMA Hideo , the Numerical Simulation Reactor Research Project Group

    … In NSRP, eight task groups are organized to cover a wide range of fusion simulation subjects: plasma fluid equilibrium stability, energetic-particle physics, integrated transport simulation, neoclassical and turbulent transport simulation, peripheral plasma transport, plasma-wall interaction, multi-hierarchy physics, and simulation science basis. …

    Plasma and Fusion Research 14(0), 3503059-3503059, 2019

    J-STAGE 

  • Core Plasma Design of the Compact Helical Reactor with a Consideration of the Equipartition Effect

    GOTO Takuya , MIYAZAWA Junichi , YANAGI Nagato , Tamura Hitoshi , TANAKA Teruya , SAKAMOTO Ryuichi , SUZUKI Chihiro , SATAKE Shinsuke , NUNAMI Masanori , YOKOYAMA Masayuki , SAGARA Akio , FFHR Design Group

    … Close investigation of the plasma operation regime has been conducted and a candidate plasma operation point of FFHR-c1 has been identified within the parameter regime that has already been confirmed in LHD experiment in view of MHD equilibrium, MHD stability and neoclassical transport. …

    Nuclear Fusion 60(7), 074001, 2018-05-08

    IR 

  • Configuration Property of the Chinese First Quasi-Axisymmetric Stellarator

    SHIMIZU Akihiro , HUANG Jie , WANG Xiangqu , LIU Hai , TANG Changjian , CFQS team , LIU Haifeng , ISOBE Mitsutaka , OKAMURA Shoichi , NISHIMURA Shin , SUZUKI Chihiro , XU Yuhong , ZHANG Xin , LIU Bing

    … Next, the effects of the bootstrap current on the quasi-axisymmetric property and the neoclassical diffusion coefficient were estimated. … The bootstrap current little affected the quasi-axisymmetric property, and a good neoclassical transport property was maintained.</p> …

    Plasma and Fusion Research 13(0), 3403123-3403123, 2018

    J-STAGE 

  • Plasma Scenario Study for HT-6M Tokamak Using BALDUR Integrated Predictive Modeling Code

    PROMPING Jiraporn , SANGAROON Siriyaporn , WISITSORASAK Apiwat , CHATTHONG Boonyarit , PICHA Roppon , ONJUN Thawatchai

    … In these simulations, a combination of turbulence and neoclassical transports is used for predicting thermal and particle transport. …

    Plasma and Fusion Research 13(0), 3403094-3403094, 2018

    J-STAGE 

  • Extended capability of the integrated transport analysis suite, TASK3D-a, for LHD experiment

    YOKOYAMA Masayuki , SEKI Ryosuke , SUZUKI Chihiro , SATO Masahiko , EMOTO Masahiko , MURAKAMI Sadayoshi , OSAKABE Masaki , Tsujimura Ii Toru , YOSHIMURA Yasuo , IDO Takeshi , OGAWA Kunihoro , SATAKE Shinsuke , SUZUKI Yasuhiro , GOTO Takuya , IDA Katsumi , Pablant N. , Gates D. , Warmer Felix , Vincenzi P. , Numerical Simulation Research Project , LHD Experiment Group

    … The integrated transport analysis suite, TASK3D-a (Analysis), has been developed to be capable for routine whole-discharge analyses of plasmas confined in three-dimensional (3D) magnetic configurations such as the LHD. … The suite has been further extended through implementing additional modules for neoclassical transport and ECH deposition for 3D configurations. …

    Nuclear Fusion 57(12), 126016, 2017-09-18

    IR 

  • Toroidal angular momentum balance during rotation changes induced by electron heating modulation in tokamak plasmas

    井戸村 泰宏

    著者所属: 日本原子力研究開発機構(JAEA)

    Physics of Plasmas 24(8), 080701\_1-080701\_5, 2017-08

    IR 

  • Multi-machine analysis of turbulent transport in helical systems via gyrokinetic simulation

    Ishizawa A. , Kishimoto Y. , Watanabe T.-H. , Sugama H. , Tanaka K. , Satake S. , Kobayashi S. , Nagasaki K. , Nakamura Y.

    … We have investigated drift-wave instability and nonlinear turbulent transport in two configurations with different magnetic field structures by means of electromagnetic gyrokinetic simulations. … First, we show that the validation against the turbulent transport in the LHD plasma is successful, and that the neoclassically optimized configuration has smaller turbulent transport. …

    Nuclear Fusion 57(6), 2017-06

    IR 

  • Development of a Real-time Simulation Tool towards Self-consistent Scenario of Plasma Start-up and Sustainment on Helical Fusion Reactor FFHR-d1

    GOTO Takuya , MIYAZAWA Junichi , SAKAMOTO Ryuichi , SUZUKI Yasuhiro , SEKI Ryosuke , SATAKE Shinsuke , HUANG B. , Nunami Masanori , YOKOYAMA Masayuki , SAGARA Akio , FFHR Design Group

    … This study closely investigates the plasma operation scenario for the LHD-type helical reactor FFHR-d1 in view of MHD equilibrium/stability, neoclassical transport, alpha energy loss and impurity effect. …

    Nuclear Fusion 57(6), 066011, 2017-04-19

    IR 

  • Characteristics of electron internal transport barrier in Heliotron J

    Kenmochi Naoki , MINAMI Takashi , Takahashi C. , Mochizuki S. , Nishioka K. , Kobayashi S. , NAGASAKI Kazunobu , Nakamura Y.

    … The formation of an electron internal transport barrier (eITB) has been observed for the first time with centrally focused electron cyclotron heating (ECH) microwaves injected into plasma in Heliotron J. … A neoclassical (NC) calculation using the Sugama–Nishimura moment method predicts that the large positive radial electric field (Er) is formed in the core region. …

    Plasma Physics and Controlled Fusion 59(5), 055013, 2017-03-27

    IR 

  • Conservation laws for collisional and turbulent transport processes in toroidal plasmas with large mean flows

    SUGAMA Hideo , NUNAMI Masanori , Nakata Motoki , Watanabe T.-H.

    … A novel gyrokinetic formulation is presented by including collisional effects into the Lagrangian variational principle to yield the governing equations for background and turbulent electromagnetic fields and gyrocenter distribution functions, which can simultaneously describe classical, neoclassical, and turbulent transport processes in toroidal plasmas with large toroidal flows on the order of the ion thermal velocity. …

    PHysics of Plasmas 24(2), 020701, 2017-02-01

    IR 

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