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Plasma Boundary Position Measurements Using Frequency Sweep Microwave Reflectometer in lhd

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Plasma Science and Technology 2009年第4期11卷 443-447页

作者： T.TOKUZAWA K.KAWAHATA K.TANAKA Y.ITO lhd experiment group 凌必利 National Institute for Fusion Science Institute of Plasma Physics Chinese Academy of Science

宽带频率悦耳的微波反射计系统，有快、稳定的频率的能力打扫操作，在大螺旋状的设备(lhd ) 被使用测量高温度的血浆的边界。微波什么时候被发射，与非凡的极化，从有它的频率的磁场的低地方面，扫了从对高度低，最小的右边的截止频率... 详细信息

宽带频率悦耳的微波反射计系统，有快、稳定的频率的能力打扫操作，在大螺旋状的设备(lhd ) 被使用测量高温度的血浆的边界。微波什么时候被发射，与非凡的极化，从有它的频率的磁场的低地方面，扫了从对高度低，最小的右边的截止频率的微波最在外面被反映。我们然后能由从截止的层测量反映的力量的变化估计血浆边界位置。

关键词：等离子体边界微波反射位置测量铲运机扫频频率可调大型螺旋装置反射系统

Magnetic Configuration Effects on Fast Ion Losses Induced by Fast Ion Driven Toroidal Alfvén Eigenmodes in the Large Helical Device

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Plasma Science and Technology 2012年第4期14卷 269-272页

作者： K.OGAWA M.ISOBE K.TOI F.WATANABE D.A.SPONG A.SHIMIZU M.OSAKABE D.S.DARROW S.OHDACHI S.SAKAKIBARA lhd experiment group Department of Energy Science and Engineering Nagoya University National Institute for Fusion Science Graduate School of Energy Science Kyoto University Oak Ridge National Laboratory Oak Ridge Princeton Plasma Physics Laboratory Princeton University

Beam-ion losses induced by fast-ion-driven toroidal Alfven eigenmodes （TAE） were measured with a scintillator-based lost fast-ion probe （SLIP） in the large helical device （lhd）. The SLIP gave simultaneously the energy E and the pitch angle X=arccos（v///v） distribution of the lost fast ions. The loss fluxes were investigated for three typical magnetic configurations of Rax-vac=3.60 m, 3.75 m. and 3.90 m, where Rax-vac is the magnetic axis position of the vacuum field. Dominant losses induced by TAEs in these three configurations were observed in the E/X regions of 50-190 keV/40°, 40-170 keV/25°, and 30-190 keV/30°, respectively. Lost-ion fluxes induced by TAEs depend clearly on the amplitude of TAE magnetic fluctuations, Rax-vac and the toroidal field strength Bt. The increment of the loss fluxes has the dependence of （bTAE/Bt）s. The power s increases from s = 1 to 3 with the increase of the magnetic axis position in finite beta plasmas.

关键词： toroidal Alfven eigenmode fast ion loss the large helical device

Improvement of Plasma Performance Using Carbon Pellet Injection in Large Helical Device

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Plasma Science and Technology 2011年第3期13卷 290-296页

作者： Shigeru MORITA Motoshi GOTO Kenichi NAGAOKA Chunfeng DONG Hangyu ZHOU Zhengying CUI Yunbo DONC Xiang GAO TKatsumi IDA Katsunori IKED Osamu KANEKO Shiyao LIN Haruhisa NAKANO Masaki OSAKABE Ryuichi SAKAMOTO Yasuhiko TAKEIRI Ang TI Katsuyoshi TSUMORI Mikiro YOSHINUMA lhd experiment group National Institute for Fusion Science Toki 509-5292 Gifu Japan Graduate University for Advanced Studies Toki 509-5292 Gifu Japan Southwestern Institute of Physics Chengdu 610041 China Institute of Plasma Physics Chinese Academy of Sciences Hefei 230031 China

A cylindrical carbon pellet with a size of 1.2L x 1.2φ mm to 1.8L x 1.8φ mm and a velocity of 100 m/s to 300 m/s was injected into large helical device （lhd） for an efficient fueling based on its deeper deposition instead of hydrogen gas puffing and ice pellet injection. Electron density increment of Ane = 10^14 cm^-3 is successfully obtained by single carbon pellet injection without plasma collapse. Typical density and temperature of the ablation plasma of the carbon pellet, e.g., 6.5× 10^16 cm^-3 and 2.5 eV for CII, are examined respectively by spectroscopic method. A confinement improvement up to 50% compared to ISS-95 stellarator scaling is clearly observed in a relatively low-density regime of ne = 2 × 10^13 cm^-3 to 4×10^13 cm^-3, and high ion temperature Ti（0） of about 6 keV is also observed with an internal transport barrier at ne = 1.2 × 10^13 cm^-3. In particular, the improvement in the ion temperature largely exceeds that observed in hydrogen gas-puffed discharges, which typically ranges below 3 keV.

关键词： carbon pellet injection confinement improvement high ion temperature

Study of first orbit losses of 1 MeV tritons using the Lorentz orbit code in the lhd

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Plasma Science and Technology 2019年第2期21卷 21-25页

作者： Kunihiro OGAWA Mitsutaka ISOBE Takeo NISHITANI Sadayoshi MURAKAMI Ryosuke SEKI Hideo NUGA Neng PU Masaki OSAKABE lhd experiment group National Institute for Fusion Science National Institutes of Natural Sciences SOKENDAI (The Graduate University for Advanced Studies) Kyoto University Kyoto-city

Shot-integrated measurement of the triton burnup ratio has been performed in the Large Helical Device. It was reported that the triton burnup ratio, defined as total DT neutron yield divided by total DD neutron yield, increases significantly in inward shifted configurations. To understand the magnetic configuration dependence of the triton burnup ratio, the first orbit loss fraction of 1 MeV tritons is evaluated by means of the Lorentz orbit code for various magnetic configurations. The first orbit loss of 1 MeV tritons is seen at t of less than 10-5 s and loss points of the triton are concentrated on the side of the helical coil case where the magnetic field is relatively weak. The significant decrease of the first orbit loss fraction by 15% is obtained with the inward shift of the magnetic axis position from 3.90 to 3.55 m. It is found that the decrease of first orbit loss is due to the reduction of the first orbit loss of transition and helically trapped tritons.

关键词： the Large Helical Device tritons energetic ion first orbit loss Lorentz orbit code

Contribution of the Large Helical Device Plasmas to Alfvén Eigenmode Physics in Toroidal Plasmas

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Plasma Science and Technology 2009年第4期11卷 377-380页

作者： K. TOI M. ISOBE M. OSAKABE F. WATANABE K. OGAWA T. TOKUZAWA A. SHIMIZU T. IDO K. IDA, T. ITO S. MORITA K. NAGAOKA K. NARIHARA M. NISHIURA S. OHDACHI S. SAKAKIBARA K. TANAKA lhd experiment group National Institute for Fusion Science Toki 509-5292 Japan Department of Energy Engineering and Science Nagoya University Nagoya 464-8601 Japan

In the large helical device （lhd） having three dimensional configuration, Alfven eigenmodes （AEs） destabilized by energetic ions are widely investigated using neutral beam heated plasmas with monotonic and non-monotonic rotational transform （l/2π） profiles. In a plasma with monotonic l/2π-profile, core-localized toroidicity-induced Alfven eigenmode （TAE） as well as global one are often observed. With the increase in the averaged toroidal beta value, defined as the ratio of total plasma pressure to toroidal magnetic pressure, core-localized TAE with low toroidal mode number becomes global. In a relatively high beta plasma with monotonic l/2π-profile, two TAEs with different toroidal mode number often interact nonlinearly and generate another modes through three wave coupling. In a plasma with non-monotonic l/2π-profile generated by intense counter neutral beam current drive, reversed shear Alfven eigenmode （RSAE） and geodesic acoustic mode （CAM） excited by energetic ions were observed for the first time in a helical plasma. Nonlinear coupling was also observed between RSAE and GAM.

关键词： alpha particles Alfven eigenmodes geodesic acoustic mode helical/stellarator

Observation of MHD Instabilities Driven by Energetic Electrons in the Large Helical Device

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Plasma Science and Technology 2015年第4期17卷 276-279页

作者： Mitsutaka ISOBE Kunihiro OGAWA Akihiro SHIMIZU Masaki OSAKABE Shin KUBO K.TOI the lhd experiment group National Institute for Fusion Science Toki 509-5292Japan Department of Fusion Science The Graduate University for Advanced Studies(SOKENDAI)Toki 509-5292Japan Department of Energy Engineering and Science Nagoya UniversityNagoya 464-8463Japan

Coherent magnetic fluctuations in an acoustic range of frequency have been regularly observed in low-density（n_e〈0.2×10^（19）m^（-3））plasmas with strong second harmonic electron cyclotron resonance heating（ECRH）on the Large Helical Device.Hard X-ray measurements indicated that energetic electrons are generated in these ECRH discharges.The magnetic fluctuations are suppressed in higher density discharges where energetic electrons are not present.The ECRH power modulation experiment indicated that the observed magnetohydrodynamic（MHD）mode has an acoustic nature rather than an Alfvenic nature.

关键词： lhd ECRH energetic electron MHD instability

Investigation of experimental Con6guration for Electron Bernstein Wave Heating on lhd

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Plasma Science and Technology 2009年第4期11卷 430-438页

作者： Hiroe IGAMI Ryosuke IKEDA Hiromi TAKAHASHI Yasuo YOSHIMURA Takashi SHIMOZUMA Shin KUBO Hitoshi TANAKA Kazunobu NAGASAKI Takashi MUTOH the lhd experiment group National Institute for Fusion Science 509-5292 Toki Japan Graduate School of Energy Science Kyoto University 606-8502 Kyoto Japan Institute of Advanced Energy Kyoto University 611-0011 Uji Japan

Investigation of experimental configuration for the electron Bernstein wave （EBW） heating by using the existing electron cyclotron heating （ECH） antennas on lhd was performed. By using an antenna installed in the lower port, direct oblique launching of the extraordinary （X-） mode from the high magnetic field side （HFS） is available. Since the parallel component of the refractive index （NIF） varies during propagation because of the inhomogeneity of the magnetic field, NH can be zero when the launched X-mode crosses the fundamental electron cyclotron resonance （ECR） layer even NⅡ is noonzero initially. In such a condition, if the electron density is above a certain level the obliquely launched X-mode can pass the fundamental ECR layer without being damped out and can be mode-converted to EBW that is absorbed at the Doppler shifted ECR layer. By using an antenna installed in the horizontal port, oblique launching from the lower magnetic field side （LFS） toward the over-dense plasma is available. Excitation of EBW via the mode conversion process of ordinary mode（O）-extraordinary mode（X）-electron Bernstein wave （B） is expected with the O-mode launching toward an appropriate direction. The O-X-B mode conversion rate and the region of power deposition were surveyed by varying the magnetic field strength and the launching direction. The results of the survey suggest that efficient heating in the core region is difficult by using the existing antenna. Rearrangement of the final mirror of the launching antenna may be needed.

关键词： lhd electron cyclotron heating （ECH） electron Bernstein wave （EBW）,high density plasma

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供应链数字化管理对企业全要素生产率的影响

中国流通经济 2024年第4期38卷 58-67页

作者：课题组张哲中国石化集团国际石油勘探开发有限公司北京市100029

数字技术的快速发展使实施供应链数字化管理成为企业适应时代发展的重要选择。研究供应链数字化管理是否能够促进企业提高全要素生产率并厘清其对企业全要素生产率的作用机制,对企业提升运营效率、增强核心竞争力具有至关重要的意义。基... 详细信息

数字技术的快速发展使实施供应链数字化管理成为企业适应时代发展的重要选择。研究供应链数字化管理是否能够促进企业提高全要素生产率并厘清其对企业全要素生产率的作用机制,对企业提升运营效率、增强核心竞争力具有至关重要的意义。基于2013—2022年我国A股上市公司数据,将供应链创新与应用试点工作视为一项准自然实验,采用双重差分模型,研究供应链数字化管理对企业全要素生产率的影响及作用机制。研究发现:供应链数字化管理能显著提高企业全要素生产率,该结论在采用双重差分倾向得分匹配(PSM-DID)检验、安慰剂检验、替换核心变量测度、排除疫情影响等一系列稳健性检验后仍显著成立。机制分析表明,供应链数字化管理通过提高企业创新能力、降低企业成本的路径提高企业全要素生产率。异质性分析表明,供应链数字化管理对东部地区企业和国有企业的促进作用更为明显。案例分析表明,中国石化集团国际石油勘探开发有限公司采用供应链数字化管理进一步验证供应链数字化管理对企业全要素生产率提高具有积极促进作用。为此,企业应深化数字技术与供应链体系的融合,积极倡导应用供应链数字化管理模式,推动企业间协同创新,共同挖掘和利用数据资源的价值,提高企业全要素生产率,从而增强自身竞争力。

关键词：供应链数字化管理企业全要素生产率核心竞争力供应链创新

Effect of Ne Glow Discharge on Ion Density Control in lhd

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Plasma Science and Technology 2004年第5期6卷 2440-2444页

作者： S.Morita M.Goto S.Masuzak H.Suzuki K.Tanaka H.Nozato Y.Takeiri J.Miyazawa lhd experimental group National Institute for Fusion Science Toki 509-5292Gifu JapanNational Institute for Fusion Science Toki 509-5292Gifu JapanNational Institute for Fusion Science Toki 509-5292Gifu JapanCollege of EngineeringChubu UniversityKasugai 487-8501AichiJapanNational Institute for Fusion Science Toki 509-5292Gifu JapanScience and Technology Center for AtomsMolecules and Ions ControlsOsaka UniversitySuita 565-0871OsakaJapanNational Institute for Fusion Science Toki 509-5292Gifu JapanNational Institute for Fusion Science Toki 509-5292Gifu Japan

Neon glow discharge cleaning was firstly attempted in Large Helical Device(lhd) instead of He glow discharge to remove hydrogen neutrals and to control the ion density, n_i.The Ne glow discharge continued for 8 hours overnight after a three-day experiment. At the secondnight H_α emission became weaker than the emission usually observed in the He glow discharge. Aclear reduction of the hydrogen influx was also observed in neutral beam injection (NBI) dischargeswith Ne puff, whereas the neon recycling was strongly enhanced with appearance of a flat densityprofile. As a result, the lowest density limit was further reduced down to 0.2 X 10^(13)cm^(-3). Theuse of Ar puff formed a peaked density profile with a high T_i of 7 keV.

关键词： hydrogen recycling Ne glow discharge ion density