51
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Toi K, Isobe M, Osakabe M, Watanabe F, Ogawa K, Yamamoto S, Nakajima N, Spong DA, Ida K, Ido T, Ito T, Morita S, Nagaoka K, Narihara K, Nishiura M, Ohdachi S, Sakakibara S, Shimizu A, Tanaka K, Todo Y, Tokuzawa T, Weller A. MHD Modes Destabilized by Energetic Ions on LHD. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst10-a10805] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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52
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Motojima O, Yamada H, Komori A, Watanabe KY, Mutoh T, Takeiri Y, Ida K, Akiyama T, Asakura N, Ashikawa N, Chikaraishi H, Cooper WA, Emoto M, Fujita T, Fujiwara M, Funaba H, Goncharov P, Goto M, Hamada Y, Higashijima S, Hino T, Hoshino M, Ichimura M, Idei H, Ido T, Ikeda K, Imagawa S, Inagaki S, Isayama A, Isobe M, Itoh T, Itoh K, Kado S, Kalinina D, Kaneba T, Kaneko O, Kato D, Kato T, Kawahata K, Kawashima H, Kawazome H, Kobuchi T, Kondo K, Kubo S, Kumazawa R, Lyon JF, Maekawa R, Mase A, Masuzaki S, Mito T, Matsuoka K, Miura Y, Miyazawa J, More R, Morisaki T, Morita S, Murakami I, Murakami S, Mutoh S, Nagaoka K, Nagasaki K, Nagayama Y, Nakamura Y, Nakanishi H, Narihara K, Narushima Y, Nishimura H, Nishimura K, Nishiura M, Nishizawa A, Noda N, Notake T, Nozato H, Ohdachi S, Ohkubo K, Ohyabu N, Oyama N, Oka Y, Okada H, Osakabe M, Ozaki T, Peterson BJ, Sagara A, Saida T, Saito K, Sakakibara S, Sakamoto M, Sakamoto R, Sasao M, Sato K, Seki T, Shimozuma T, Shoji M, Sudo S, Takagi S, Takahashi Y, Takase Y, Takenaga H, Takeuchi N, Tamura N, Tanaka K, Tanaka M, Toi K, Takahata K, Tokuzawa T, Torii Y, Tsumori K, Watanabe F, Watanabe M, Watanabe T, Watari T, Yamada I, Yamada S, Yamaguchi T, Yamamoto S, Yamazaki K, Yanagi N, Yokoyama M, Yoshida N, Yoshimura S, Yoshimura Y, Yoshinuma M. Review on the Progress of the LHD Experiment. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst04-a535] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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53
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Hoshino K, Suzuki T, Isayama A, Ide S, Takenaga H, Kubo H, Fujita T, Kamada Y, Fujii T, Tsuda T, Ida K, Inagaki S. Electron Cyclotron Heating Applied to the JT-60U Tokamak. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst08-a1659] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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54
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Yokoyama M, Maassberg H, Beidler CD, Tribaldos V, Ida K, Castejón F, Estrada T, Fujisawa A, Minami T, Shimozuma T, Takeiri Y, Herranz J, Murakami S, Yamada H. Common Features of Core Electron-Root Confinement in Helical Devices. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst06-a1254] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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55
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Emoto M, Yoshinuma M, Yoshida M, Nakanishi H, Iwata C, Ohsuna M, Nonomura M, Imazu S, Yokota M, Aoyagi M, Ogawa H, Ida K, Watanabe K, Kaneko O. Overview of the LHD central control room data monitoring environment. FUSION ENGINEERING AND DESIGN 2016. [DOI: 10.1016/j.fusengdes.2016.02.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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56
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Kobayashi S, Ohshima S, Matsuda H, Lu XX, Kokubu D, Ida K, Kobayashi T, Yoshinuma M, Kado S, Oishi T, Nagasaki K, Okada H, Minami T, Yamamoto S, Nakamura Y, Ishizawa A, Kenmochi N, Otani Y, Konoshima S, Mizuuchi T. Development of beam emission spectroscopy for turbulence transport study in Heliotron J. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:11E519. [PMID: 27910398 DOI: 10.1063/1.4959949] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This paper describes the development study of the beam emission spectroscopy (BES) for the turbulent transport study in Heliotron J. Modification of the sightlines (10 × 4 for edge and 10 × 2 for edge) enables us to obtain 2-dimensional BES imaging. The cooling effect on the reduction in the electrical noise of avalanche photodiode (APD) assembly has been investigated using a refrigerant cooling system. When the temperature of the APD element has set to be -20 °C, the electrical noise can be reduced more than 50%. The measurement error of the phase difference in the case of low signal level has been tested by two light-emitting diode lamps. The APD cooling has an effect to improve the measurement error at the low signal level of APD.
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Ono M, Ida K, Kobayashi T, Yoshinuma M, Nakamura Y, Kisaki M, Nakano H, Moon C. Beam emission spectroscopy with radially and poloidally elongated optical sightlines. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:11E559. [PMID: 27910654 DOI: 10.1063/1.4963311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 09/12/2016] [Indexed: 06/06/2023]
Abstract
Beam emission spectroscopy is widely used as local density fluctuation measurement of fusion plasmas. We have installed a beam emission spectroscopy system in the large helical device (LHD) with radially and poloidally elongated optical configuration to enhance both signal-to-noise ratio and wavenumber sensitivity in radial and poloidal directions. The calculation considering the integral effect of the line of sight showed the radially and poloidally elongated sightlines have increased sensitivity compared with the square shaped bundle design of the same sampling area.
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58
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Kobayashi T, Itoh K, Ido T, Kamiya K, Itoh SI, Miura Y, Nagashima Y, Fujisawa A, Inagaki S, Ida K, Hoshino K. Experimental Identification of Electric Field Excitation Mechanisms in a Structural Transition of Tokamak Plasmas. Sci Rep 2016; 6:30720. [PMID: 27489128 PMCID: PMC4973265 DOI: 10.1038/srep30720] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 07/06/2016] [Indexed: 11/09/2022] Open
Abstract
Self-regulation between structure and turbulence, which is a fundamental process in the complex system, has been widely regarded as one of the central issues in modern physics. A typical example of that in magnetically confined plasmas is the Low confinement mode to High confinement mode (L-H) transition, which is intensely studied for more than thirty years since it provides a confinement improvement necessary for the realization of the fusion reactor. An essential issue in the L-H transition physics is the mechanism of the abrupt "radial" electric field generation in toroidal plasmas. To date, several models for the L-H transition have been proposed but the systematic experimental validation is still challenging. Here we report the systematic and quantitative model validations of the radial electric field excitation mechanism for the first time, using a data set of the turbulence and the radial electric field having a high spatiotemporal resolution. Examining time derivative of Poisson's equation, the sum of the loss-cone loss current and the neoclassical bulk viscosity current is found to behave as the experimentally observed radial current that excites the radial electric field within a few factors of magnitude.
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59
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Kobayashi T, Ida K, Itoh K, Yoshinuma M, Moon C, Inagaki S, Yamada I, Funaba H, Yasuhara R, Tsuchiya H, Ohdachi S, Yoshimura Y, Igami H, Shimozuma T, Kubo S, Tsujimura TI. Reconstruction of high temporal resolution Thomson scattering data during a modulated electron cyclotron resonance heating using conditional averaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:043505. [PMID: 27131672 DOI: 10.1063/1.4945258] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This paper provides a software application of the sampling scope concept for fusion research. The time evolution of Thomson scattering data is reconstructed with a high temporal resolution during a modulated electron cyclotron resonance heating (MECH) phase. The amplitude profile and the delay time profile of the heat pulse propagation are obtained from the reconstructed signal for discharges having on-axis and off-axis MECH depositions. The results are found to be consistent with the MECH deposition.
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60
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Lesur M, Itoh K, Ido T, Osakabe M, Ogawa K, Shimizu A, Sasaki M, Ida K, Inagaki S, Itoh SI. Nonlinear Excitation of Subcritical Instabilities in a Toroidal Plasma. PHYSICAL REVIEW LETTERS 2016; 116:015003. [PMID: 26799024 DOI: 10.1103/physrevlett.116.015003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Indexed: 06/05/2023]
Abstract
In a collisionless plasma, it is known that linearly stable modes can be destabilized (subcritically) by the presence of structures in phase space. However, nonlinear growth requires the presence of a seed structure with a relatively large threshold in amplitude. We demonstrate that, in the presence of another, linearly unstable (supercritical) mode, wave-wave coupling can provide a seed, which is significantly below the threshold, but can still grow by (and only by) the collaboration of fluid and kinetic nonlinearities. By modeling the subcritical mode kinetically, and the impact of the supercritical mode by simple wave-wave coupling equations, it is shown that this new kind of subcritical instability can be triggered, even when the frequency of the supercritical mode is rapidly sweeping. The model is applied to the bursty onset of geodesic acoustic modes in a LHD experiment. The model recovers several key features such as relative amplitude, time scales, and phase relations. It suggests that the strongest bursts are subcritical instabilities, driven by this mechanism of combined fluid and kinetic nonlinearities.
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61
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Ido T, Itoh K, Osakabe M, Lesur M, Shimizu A, Ogawa K, Toi K, Nishiura M, Kato S, Sasaki M, Ida K, Inagaki S, Itoh SI. Strong Destabilization of Stable Modes with a Half-Frequency Associated with Chirping Geodesic Acoustic Modes in the Large Helical Device. PHYSICAL REVIEW LETTERS 2016; 116:015002. [PMID: 26799023 DOI: 10.1103/physrevlett.116.015002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Indexed: 06/05/2023]
Abstract
Abrupt and strong excitation of a mode has been observed when the frequency of a chirping energetic-particle driven geodesic acoustic mode (EGAM) reaches twice the geodesic acoustic mode (GAM) frequency. The frequency of the secondary mode is the GAM frequency, which is a half-frequency of the primary EGAM. Based on the analysis of spatial structures, the secondary mode is identified as a GAM. The phase relation between the secondary mode and the primary EGAM is locked, and the evolution of the growth rate of the secondary mode indicates nonlinear excitation. The results suggest that the primary mode (EGAM) contributes to nonlinear destabilization of a subcritical mode.
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62
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Ida K, Yoshinuma M, Wieland B, Goto M, Nakamura Y, Kobayashi M, Murakami I, Moon C. Measurement of radial profiles of density ratio of helium to hydrogen ion using charge exchange spectroscopy with two-wavelength spectrometer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:123514. [PMID: 26724034 DOI: 10.1063/1.4939032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Radial profiles of density ratio of helium to hydrogen ions are measured using the charge exchange spectroscopy technique with the two-wavelength spectrometer system in the large helical device. The two-wavelength spectrometer system consists of a dichroic mirror box, a spectrometer with two grating and two camera lenses, and one CCD detector. The dichroic mirror box is used to divide the light of one fiber from the plasma to two fibers, one for HeII (λ = 468.6 nm) and the other for H(α) (λ = 656.3 nm), that are connected to the entrance slit of the spectrometer to eliminate the interference between the HeII and the H(α) spectra on the CCD. This system provides a simultaneous measurement of helium and hydrogen ion density ratio at 8 exact same locations (8 spatial channels) with a time resolution of >40 ms in the wide range of the density ratio of 0.05-5.
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63
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Ida K, Yoshinuma M, Tsuchiya H, Kobayashi T, Suzuki C, Yokoyama M, Shimizu A, Nagaoka K, Inagaki S, Itoh K. Erratum: Flow damping due to stochastization of the magnetic field. Nat Commun 2015; 6:6531. [PMID: 25739874 PMCID: PMC4366482 DOI: 10.1038/ncomms7531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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64
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Kawai K, Sasaki Z, Misaki F, Ida K, Kubota Y. Endoscopic diagnosis of intestinal metaplasia of the stomach and its evaluation as a precancerous lesion. FRONTIERS OF GASTROINTESTINAL RESEARCH 2015; 5:140-8. [PMID: 499978 DOI: 10.1159/000402321] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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65
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Ko WH, Lee HH, Jeon YM, Ida K, Lee JH, Yoon SW, Lee KD, Bae YS, Oh YK, Kwak JG. Rotation characteristics during the resonant magnetic perturbation induced edge localized mode suppression on the KSTAR. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:11E413. [PMID: 25430320 DOI: 10.1063/1.4890402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Measuring rotation profiles with a reliable spatial resolution is one of the critical diagnostics in understanding the plasma behavior especially for the edge transport. In the KSTAR experiments, it has been consistently observed from the charge exchange spectroscopy measurements that the magnetic perturbations not only suppresses edge localized modes (ELMs) but also reduces toroidal rotations. In this paper, toroidal velocities of the carbon impurity and their profile evolutions during ELMy and ELM-suppressed phases are presented. The rotation profiles are shown to collapse immediately after an ELM burst and continue to build up until the next burst that accompanies another collapse. Toroidal rotations following the resonant magnetic perturbations applications are observed to be reduced along with the ELMs suppressed.
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66
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Wei YL, Yu DL, Liu L, Ida K, von Hellermann M, Cao JY, Sun AP, Ma Q, Chen WJ, Liu Y, Yan LW, Yang QW, Duan XR, Liu Y. High spatial and temporal resolution charge exchange recombination spectroscopy on the HL-2A tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:103503. [PMID: 25362389 DOI: 10.1063/1.4897186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A 32/64-channel charge exchange recombination spectroscopy (CXRS) diagnostic system is developed on the HL-2A tokamak (R = 1.65 m, a = 0.4 m), monitoring plasma ion temperature and toroidal rotation velocity simultaneously. A high throughput spectrometer (F/2.8) and a pitch-controlled fiber bundle enable the temporal resolution of the system up to 400 Hz. The observation geometry and an optimized optic system enable the highest radial resolution up to ∼1 cm at the plasma edge. The CXRS system monitors the carbon line emission (C VI, n = 8-7, 529.06 nm) whose Doppler broadening and Doppler shift provide ion temperature and plasma rotation velocity during the neutral beam injection. The composite CX spectral data are analyzed by the atomic data and analysis structure charge exchange spectroscopy fitting (ADAS CXSFIT) code. First experimental results are shown for the case of HL-2A plasmas with sawtooth oscillations, electron cyclotron resonance heating, and edge transport barrier during the high-confinement mode (H-mode).
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67
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Emoto M, Ida K, Suzuki C, Yoshida M, Akiyama T, Nakamura Y, Sakamoto R, Yokoyama M, Yoshinuma M. Automatically processing physical data from LHD experiments. FUSION ENGINEERING AND DESIGN 2014. [DOI: 10.1016/j.fusengdes.2014.02.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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68
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Kobayashi T, Itoh K, Ido T, Kamiya K, Itoh SI, Miura Y, Nagashima Y, Fujisawa A, Inagaki S, Ida K, Hoshino K. Spatiotemporal structures of edge limit-cycle oscillation before L-to-H transition in the JFT-2M tokamak. PHYSICAL REVIEW LETTERS 2013; 111:035002. [PMID: 23909334 DOI: 10.1103/physrevlett.111.035002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Indexed: 06/02/2023]
Abstract
In this Letter, we report analyses of spatiotemporal dynamics of turbulence and structure in the limit-cycle oscillation (LCO) that precedes an L-to-H transition. Zonal flows are not observed during LCO, and the oscillation is the periodic generations or decays of barrier with edge-localized mean flow. Oscillatory Reynolds stress is found to be too small to accelerate the LCO flow, by considering the dielectric constant in magnetized toroidal plasmas. Propagation of changes of the density gradient and turbulence amplitude into the core is also observed.
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69
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Seol J, Lee SG, Park BH, Lee HH, Terzolo L, Shaing KC, You KI, Yun GS, Kim CC, Lee KD, Ko WH, Kwak JG, Kim WC, Oh YK, Kim JY, Kim SS, Ida K. Effects of electron-cyclotron-resonance-heating-induced internal kink mode on the toroidal rotation in the KSTAR Tokamak. PHYSICAL REVIEW LETTERS 2012; 109:195003. [PMID: 23215391 DOI: 10.1103/physrevlett.109.195003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Indexed: 06/01/2023]
Abstract
It is observed that the magnitude of the toroidal rotation speed is reduced by the central electron cyclotron resonance heating (ECRH) regardless of the direction of the toroidal rotation. The magnetohydrodynamics activities generally appear with the rotation change due to ECRH. It is shown that the internal kink mode is induced by the central ECRH and breaks the toroidal symmetry. When the magnetohydrodynamics activities are present, the toroidal plasma viscosity is not negligible. The observed effects of ECRH on the toroidal plasma rotation are explained by the neoclassical toroidal viscosity in this Letter. It is found that the neoclassical toroidal viscosity torque caused by the internal kink mode damps the toroidal rotation.
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70
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Tokuzawa T, Ejiri A, Kawahata K, Tanaka K, Yamada I, Yoshinuma M, Ida K, Suzuki C. Microwave Doppler reflectometer system in LHD. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:10E322. [PMID: 23126980 DOI: 10.1063/1.4733736] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In order to measure the poloidal rotation velocity, a Doppler reflectometer has been developed in Large Helical Device (LHD). A remotely controlled antenna tilting system has been installed in an LHD vacuum vessel. A synthesizer is used as the source, and the operation microwave frequency ranges are ka-band and V-band. In LHD last experimental campaign we obtained the Doppler shifted signal, which was consistent with CXRS measurements.
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71
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Ida K, Kamiya K, Isayama A, Sakamoto Y. Reduction of ion thermal diffusivity inside a magnetic island in JT-60U tokamak plasma. PHYSICAL REVIEW LETTERS 2012; 109:065001. [PMID: 23006274 DOI: 10.1103/physrevlett.109.065001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Indexed: 06/01/2023]
Abstract
A peaked ion temperature profile is observed inside the magnetic island during mode locking after the back transition from H mode to L mode in JT-60U. The thermal diffusivity evaluated inside the magnetic island is 0.1 m(2)/s, which is much smaller than that outside the magnetic island by an order of magnitude. The present experiment gives clear evidence that ion heat transport inside a magnetic island can bifurcate and the transport level can be suppressed to the very low level associated with the strong flow shear at the boundary.
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72
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Igami H, Yoshimura Y, Takahashi H, Shimozuma T, Kubo S, Idei H, Nishiura M, Ogasawara S, Makino R, Ohdachi S, Ida K, Yoshinuma M, Ido T, Shimizu A, Tamura N, Inagaki S, Mutoh T. Progress of ECRH by EBW in over-dense plasmas and controlling the confinement regime by ECCD with high power launching in LHD. EPJ WEB OF CONFERENCES 2012. [DOI: 10.1051/epjconf/20123202006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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73
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Miyazawa J, Goto T, Morisaki T, Goto M, Sakamoto R, Motojima G, Peterson B, Suzuki C, Ida K, Yamada H, Sagara A. Direct extrapolation of radial profile data to a self-ignited fusion reactor based on the gyro-Bohm model. FUSION ENGINEERING AND DESIGN 2011. [DOI: 10.1016/j.fusengdes.2011.06.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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74
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Nakamura S, Ida K, Ohgaku T. Investigation of the yield process by deformation luminescence of X-ray irradiated KCl:Ca2+. RADIAT MEAS 2011. [DOI: 10.1016/j.radmeas.2011.06.053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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75
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Inagaki S, Tokuzawa T, Itoh K, Ida K, Itoh SI, Tamura N, Sakakibara S, Kasuya N, Fujisawa A, Kubo S, Shimozuma T, Ido T, Nishimura S, Arakawa H, Kobayashi T, Tanaka K, Nagayama Y, Kawahata K, Sudo S, Yamada H, Komori A. Observation of long-distance radial correlation in toroidal plasma turbulence. PHYSICAL REVIEW LETTERS 2011; 107:115001. [PMID: 22026678 DOI: 10.1103/physrevlett.107.115001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Indexed: 05/31/2023]
Abstract
This Letter presents the discovery of macroscale electron temperature fluctuations with a long radial correlation length comparable to the plasma minor radius in a toroidal plasma. Their spatiotemporal structure is characterized by a low frequency of ∼1-3 kHz, ballistic radial propagation, a poloidal or toroidal mode number of m/n=1/1 (or 2/1), and an amplitude of ∼2% at maximum. Nonlinear coupling between the long-range fluctuations and the microscopic fluctuations is identified. A change of the amplitude of the long-range fluctuation is transmitted across the plasma radius at the velocity which is of the order of the drift velocity.
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76
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Yoshimoto M, Takebayashi T, Kawaguchi S, Tsuda H, Ida K, Wada T, Suzuki D, Yamashita T. Minimally Invasive Technique for Decompression of Lumbar Foraminal Stenosis Using a Spinal Microendoscope: Technical Note. ACTA ACUST UNITED AC 2011; 54:142-6. [DOI: 10.1055/s-0031-1279716] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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77
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Kado S, Oishi T, Yoshinuma M, Ida K. Grating spectrometer system for beam emission spectroscopy diagnostics using high-energy negative-ion-based neutral beam injection on LHD. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:10D720. [PMID: 21033913 DOI: 10.1063/1.3479113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A beam emission spectroscopy (BES) system was developed for density gradient and fluctuation diagnostics in the Large Helical Device (LHD). In order to cover the large Doppler shift of the Hα beam emission because of the high-energy negative-ion-based neutral beam atom (acceleration voltage V(acc)=90-170 kV) and the large motional Stark splitting due to the large v×B field (magnetic field B=3.0 T), a grating spectrometer was used instead of a conventional interference filter system. The reciprocal linear dispersion is about 2 nm/mm, which is sufficient to cover the motional Stark effect spectra using an optical fiber with a diameter of 1 mm.
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78
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Oishi T, Kado S, Ida K, Yoshinuma M, Nakano H, Yamazaki K. Poloidal beam emission spectroscopy system for the measurement of density fluctuations in Large Helical Device. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:10D719. [PMID: 21033912 DOI: 10.1063/1.3478685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A system of beam emission spectroscopy (BES) for density fluctuation measurements having the sightlines passing through the plasma in the poloidal direction was developed in the Large Helical Device (LHD). Even though the angle between the beam and the sightline is slightly larger than a right angle, Doppler-shifted beam emission can be distinguished from background emission because of the high energy (120-170 keV) of the neutral beam for heating with negative ion sources. Spatial resolution is about 0.1-0.2 in the normalized radius. Compared with the prototype BES system with toroidal sightlines, the BES system with poloidal sightlines showed improved spatial resolution.
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79
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Ito T, Osakabe M, Ida K, Yoshinuma M, Kobayashi M, Goto M, Murakami S, Isobe M, Kobayashi S, Toi K, Ogawa K, Takeiri Y, Okamura S. Fast ion charge exchange spectroscopy adapted for tangential viewing geometry in LHD. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:10D327. [PMID: 21033849 DOI: 10.1063/1.3502331] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A tangential Fast Ion Charge eXchange Spectroscopy is newly applied on a Large Helical Device (LHD) for co/countercirculating fast ions, which are produced by high energy tangential negative-ion based neutral beam injection. With this new observation geometry, both the tangential-neutral beam (NB) and a low-energy radial-NB based on positive ions can be utilized as probe beams of the measurement. We have successfully observed Doppler-shifted H-alpha lights due to the charge exchange process between the probing NB and circulating hydrogen ions of around 100 keV in LHD plasmas.
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80
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Toi K, Watanabe F, Tokuzawa T, Ida K, Morita S, Ido T, Shimizu A, Isobe M, Ogawa K, Spong DA, Todo Y, Watari T, Ohdachi S, Sakakibara S, Yamamoto S, Inagaki S, Narihara K, Osakabe M, Nagaoka K, Narushima Y, Watanabe KY, Funaba H, Goto M, Ikeda K, Ito T, Kaneko O, Kubo S, Murakami S, Minami T, Miyazawa J, Nagayama Y, Nishiura M, Oka Y, Sakamoto R, Shimozuma T, Takeiri Y, Tanaka K, Tsumori K, Yamada I, Yoshinuma M, Kawahata K, Komori A. Observation of reversed-shear Alfvén eigenmodes excited by energetic ions in a helical plasma. PHYSICAL REVIEW LETTERS 2010; 105:145003. [PMID: 21230839 DOI: 10.1103/physrevlett.105.145003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2008] [Indexed: 05/30/2023]
Abstract
Reversed-shear Alfvén eigenmodes were observed for the first time in a helical plasma having negative q₀'' (the curvature of the safety factor q at the zero shear layer). The frequency is swept downward and upward sequentially via the time variation in the maximum of q. The eigenmodes calculated by ideal MHD theory are consistent with the experimental data. The frequency sweeping is mainly determined by the effects of energetic ions and the bulk pressure gradient. Coupling of reversed-shear Alfvén eigenmodes with energetic ion driven geodesic acoustic modes generates a multitude of frequency-sweeping modes.
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81
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Ida K, Inagaki S, Yoshinuma M, Tamura N, Morisaki T. Potential Structure and Transport in the Magnetic Island in LHD. FUSION SCIENCE AND TECHNOLOGY 2010. [DOI: 10.13182/fst10-a10798] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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82
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Ida K, Yoshinuma M, Tanaka K, Sakamoto R, Inagaki S. Interplay between Particle Momentum and Heat Transport. FUSION SCIENCE AND TECHNOLOGY 2010. [DOI: 10.13182/fst10-a10802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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83
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Kawahata K, Peterson BJ, Akiyama T, Ashikawa N, Emoto M, Funaba H, Hamada Y, Ida K, Inagaki S, Ido T, Isobe M, Goto M, Mase A, Masuzaki S, Michael C, Morisaki T, Morita S, Muto S, Nagayama Y, Nakamura Y, Nakanishi H, Sakamoto R, Narihara K, Nishiura M, Ohdachi S, Okajima S, Osakabe M, Sakakibara S, Sanin A, Sasao M, Sato K, Shimizu A, Shoji M, Sudo S, Tamura N, Tanaka K, Toi K, Tokuzawa T, Veshchev EV, Vyacheslavov LN, Yamada I, Yoshinuma M. Overview of LHD Plasma Diagnostics. FUSION SCIENCE AND TECHNOLOGY 2010. [DOI: 10.13182/fst10-a10819] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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84
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Kamiya K, Ida K, Sakamoto Y, Matsunaga G, Kojima A, Urano H, Oyama N, Koide Y, Kamada Y. Observation of a complex multistage transition in the JT-60U H-mode edge. PHYSICAL REVIEW LETTERS 2010; 105:045004. [PMID: 20867854 DOI: 10.1103/physrevlett.105.045004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Indexed: 05/29/2023]
Abstract
A complex multistage transition of the edge radial electric field is observed in JT-60U H-mode phase without edge localized mode. An interesting feature is that the poloidal rotation velocity of the carbon impurity ions changes in the later H-phase without a comparable change in the main ion pressure gradient, indicating a change in the parallel momentum (and particle) balance channel.
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85
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Makimoto A, Mugishima H, Taga T, Ishida Y, Nagatoshi Y, Ida K, Kumagai M, Kimura T, Ohashi Y, Kaneko M. An investigator-initiated registration-directed phase I/II clinical trial of irinotecan hydrochroride for refractory pediatric solid tumors. J Clin Oncol 2010. [DOI: 10.1200/jco.2010.28.15_suppl.9547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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86
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Hiyama E, Kamimatsuse A, Kamei N, Watanabe K, Hishiki T, Tajiri T, Ida K, Yano M, Kondo S, Sasaki F. Cisplatin plus pirarubicin chemotherapy and combination ifomide, etoposide, pirarubicin, and carboplatin chemotherapy for hepatoblastoma. J Clin Oncol 2010. [DOI: 10.1200/jco.2010.28.15_suppl.9534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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87
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Yamada H, Imagawa S, Takeiri Y, Kaneko O, Mutoh T, Mito T, Chikaraishi H, Hamaguchi S, Ida K, Igami H, Ikeda K, Kasahara H, Kobayashi M, Kubo S, Kumazawa R, Maekawa R, Masuzaki S, Miyazawa J, Morisaki T, Morita S, Nagaoka K, Nakamura Y, Narushima Y, Osakabe M, Saito K, Sakakibara S, Sakamoto R, Seki T, Shimozuma T, Shoji M, Suzuki Y, Takahata K, Tamura H, Tsumori K, Watanabe K, Yamada S, Yanagi N, Yoshimura Y, Kawahata K, Ohyabu N, Komori A, Motojima O. 10 years of engineering and physics achievements by the Large Helical Device project. FUSION ENGINEERING AND DESIGN 2009. [DOI: 10.1016/j.fusengdes.2009.01.068] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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88
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Suzuki C, Ida K, Kobuchi T, Yoshinuma M. Energy resolved soft x-ray imaging using a charge coupled device camera for long pulse discharges in the Large Helical Device. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:10E929. [PMID: 19044584 DOI: 10.1063/1.2953676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Energy resolved soft x-ray imaging system using a charge coupled device camera and a multifilter disk has recently been installed to the Large Helical Device for the measurements in the long pulse discharges. Eight images with different cutoff energies are measured sequentially during a single discharge by rotating a filter disk mounting eight beryllium filters with different thicknesses. A tangential line-integrated profile for a specific photon energy range can be obtained by taking intensity difference between two images measured with a filter pair of adjacent thicknesses. The typical photon energy corresponding to each difference ranges from 1.9 to 4.8 keV with the bandwidth of 2-3 keV. In the initial results, the difference in the line-integrated soft x-ray profile by the energy range has been clearly observed. This diagnostic method can possibly be applied to the observation of the dependence of two dimensional soft x-ray profile on photon energy range especially if local non-Maxwellian component appears in electron energy distribution function.
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89
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Takusagawa H, Yamamura S, Endo S, Ida K, Sugawara Y. Analysis of crystal growth of trigonal ribonuclease A from bovine pancreas. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308081348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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90
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Ida K, Sakamoto Y, Takenaga H, Oyama N, Itoh K, Yoshinuma M, Inagaki S, Kobuchi T, Isayama A, Suzuki T, Fujita T, Matsunaga G, Koide Y, Yoshida M, Ide S, Kamada Y. Transition between internal transport barriers with different temperature-profile curvatures in JT-60U Tokamak plasmas. PHYSICAL REVIEW LETTERS 2008; 101:055003. [PMID: 18764400 DOI: 10.1103/physrevlett.101.055003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 03/01/2008] [Indexed: 05/26/2023]
Abstract
A spontaneous transition phenomena between two states of a plasma with an internal transport barrier (ITB) is observed in the steady-state phase of the magnetic shear in the negative magnetic shear plasma in the JT-60U tokamak. These two ITB states are characterized by different profiles of the second radial derivative of the ion temperature inside the ITB region (one has a weak concave shape and the other has a strong convex shape) and by different degrees of sharpness of the interfaces between the L mode and the ITB region, which is determined by the turbulence penetration into the ITB region.
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91
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Ida K, Sakamoto Y, Yoshinuma M, Inagaki S, Kobuchi T, Matsunaga G, Koide Y. Measurement of derivative of ion temperature using high spatial resolution charge exchange spectroscopy with space modulation optics. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:053506. [PMID: 18513068 DOI: 10.1063/1.2921702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A new technique to measure the first and second derivatives of the ion temperature profile has been developed by using a charge exchange spectroscopy system with space modulation optics. The space observed is scanned up to +/-3 cm with a cosine wave modulation frequency up to 30 Hz by shifting the object lens in front of the optical fiber bundle by 0.5 mm with a piezoelement. The first and second derivatives of ion temperature are derived from the modulation component of the ion temperature measured by using Fourier series expansion.
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92
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Ida K, Inagaki S, Yoshinuma M, Narushima Y, Itoh K, Kobuchi T, Watanabe KY, Funaba H, Sakakibara S, Morisaki T. Bifurcation phenomena of a magnetic island at a rational surface in a magnetic-shear control experiment. PHYSICAL REVIEW LETTERS 2008; 100:045003. [PMID: 18352289 DOI: 10.1103/physrevlett.100.045003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Indexed: 05/26/2023]
Abstract
Three states of a magnetic island are observed when the magnetic shear at the rational surface is modified using inductive current associated with the neutral beam current drive in the Large Helical Device. One state is the healed magnetic island with a zero island width. The second state is the saturated magnetic island with partial flattening of the T(e) profile. The third state is characterized by the global flattening of the T(e) profile in the core region. As the plasma assumes each of the three states consecutively through a bifurcation process a clear hysteresis in the relation between the size of the magnetic island and the magnetic shear is observed.
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93
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Fujisawa A, Itoh K, Shimizu A, Nakano H, Ohshima S, Iguchi H, Matsuoka K, Okamura S, Minami T, Yoshimura Y, Nagaoka K, Ida K, Toi K, Takahashi C, Kojima M, Nishimura S, Isobe M, Suzuki C, Akiyama T, Nagashima Y, Itoh SI, Diamond PH. Experimental evidence of a zonal magnetic field in a toroidal plasma. PHYSICAL REVIEW LETTERS 2007; 98:165001. [PMID: 17501426 DOI: 10.1103/physrevlett.98.165001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Indexed: 05/15/2023]
Abstract
A zonal magnetic field is found in a toroidal plasma. The magnetic field has a symmetric bandlike structure, which is uniform in the toroidal and poloidal directions and varies radially with a finite wavelength of mesoscale, which is analogous to zonal flows. A time-dependent bicoherence analysis reveals that the magnetic field should be generated by the background plasma turbulence. The discovery is classified as a new kind of phenomenon of structured magnetic field generation, giving insight into phenomena such as dipole field generation in rotational planets.
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94
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Yamada H, Suzuki Y, Ida K, Yoshinuma M, Kobuchi T, Watanabe KY, Tanaka K, Tokuzawa T. Observation of Equilibria with a Double Magnetic Axis in LHD. FUSION SCIENCE AND TECHNOLOGY 2007. [DOI: 10.13182/fst07-a1295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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95
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Okamura S, Akiyama T, Fujisawa A, Ida K, Iguchi H, Isobe M, Kado S, Minami T, Nagaoka K, Nakamura K, Nishimura S, Matsuoka K, Matsushita H, Nakano H, Ohshima S, Oishi T, Shimizu A, Suzuki C, Takahashi C, Toi K, Yoshimura Y, Yoshinu M. Improved Confinement and Related Physics Study in the Compact Helical System. FUSION SCIENCE AND TECHNOLOGY 2007. [DOI: 10.13182/fst07-a1286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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96
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Nakamura Y, Yokoyama M, Nakajima N, Watanabe KY, Funaba H, Suzuki Y, Ida K, Sakakibara S, Yamada H, Fukuyama A, Murakami S. Development of Integrated Simulation System for Helical Plasmas. FUSION SCIENCE AND TECHNOLOGY 2006. [DOI: 10.13182/fst06-a1269] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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97
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Ida K, Inagaki S, Sakamoto R, Tanaka K, Funaba H, Takeiri Y, Ikeda K, Michael C, Tokuzawa T, Yamada H, Nagayama Y, Itoh K, Kaneko O, Komori A, Motojima O. Slow transition of energy transport in high-temperature plasmas. PHYSICAL REVIEW LETTERS 2006; 96:125006. [PMID: 16605919 DOI: 10.1103/physrevlett.96.125006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Indexed: 05/08/2023]
Abstract
A new slow transition process for energy transport in magnetically confined plasmas is reported. The slow transition is characterized by the change between two metastable transport conditions characterized by a weak and a strong electron temperature (Te) dependence of normalized heat flux. These two branches are found to merge at the critical gradient. In metastable transport, the derivative of normalized heat flux to the Te gradient, [EQUATION: SEE TEXT], is positive, while it becomes negative during the transition phase. The time for the transition increases as the normalized Te gradient is increased and exceeds the transport time scale characterized by the global energy confinement time.
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98
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Tsuchiya K, Akiba M, Azechi H, Fujii T, Fujita T, Fujiwara M, Hamamatsu K, Hashizume H, Hayashi N, Horiike H, Hosogane N, Ichimura M, Ida K, Ikeda Y, Imai T, Inoue N, Ishida S, Itoh S, Kamada Y, Kawashima H, Kikuchi M, Kimura A, Kizu K, Kubo H, Kudo Y, Kurihara K, Kurita G, Kuriyama M, Masaki K, Matsukawa M, Matsuoka M, Miura Y, Miura Y, Miya N, Morioka A, Nakamura K, Ninomiya H, Nishimura A, Okano K, Okuno K, Sagara A, Sakamoto M, Sakurai S, Sato K, Shimada R, Shimizu A, Suzuki T, Takahashi H, Takase Y, Takechi M, Tamai H, Tanaka S, Tsutsui H, Uesugi Y, Yatsu K, Yoshida N. Engineering design and control scenario for steady-state high-beta operation in National Centralized Tokamak. FUSION ENGINEERING AND DESIGN 2006. [DOI: 10.1016/j.fusengdes.2005.08.066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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99
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Ida K, Suguro M, Suzuki H. Crystal structure of L-phenylalanine oxidase. Acta Crystallogr A 2005. [DOI: 10.1107/s0108767305091750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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100
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Yamamoto M, Ueno G, Hirose R, Ida K, Kumasaka T. Automated operation of protein crystallography beamlines at the SPring-8. Acta Crystallogr A 2005. [DOI: 10.1107/s0108767305097631] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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