Formation of Second-Stable, Ultra-High-Beta Spherical Tokamaks by Use of Field-Reversed Configuration

利用场反转构型形成第二稳定、超高β球形托卡马克

• 批准号: 12480115
• 负责人: ONO Yasushi
• 金额: $ 8.06万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12480115/
• 关键词: Spherical Tokamak; Field-Reversed Configuration; Second Stability; Ballooning Instability; Plasma Merging; Magnetic Reconnection; Absolute Minimum B Configuration; Dimagnetism; ブルーニング不安定; 第二安定化

Novel CS(center solenoid)-less formations of ultra-high-beta Spherical Tokamaks (ST) have been developed in the TS-3 and TS-4 merging experiment using high power heating of magnetic reconnection. In Type-A merging, two STs were merged together to build up the plasma beta up to β_T【approximately equal】0.5. High power heating of reconnection transformed the low-beta merging STs into a high-beta ST within a short reconnection time. In Type-B merging, an oblate FRC was first formed by two merging spheromaks with .opposing toroidal field, and was transformed into an ultra-high-beta (β-_r【approximately equal】0.8) ST by applying external toroidal magnetic field. The ultra-high-beta STs by Type-B merging were found to have diamagnetic toroidal field and absolute minimum-B type configurations. We made (1) the BALLOO code stability analyzes of the produced STs for the first time and concluded formations of the first-stable / marginally ined ballooning-stable regime was almost consistent with measured high-n instabilities. The unstable STs by both merging formations suffered from high-n magnetic fluctuation and disrupted within a 10-30 Alfven time. Our experimental observation identified the ballooning stability window consistent with measured high-n instabilities. The stable regime became larger significantly by increasing the hollowness of current profile and broadness of pressure profile. This paper also addresses (2) normalized betas β_N of thus produced STs as large as 6-17 for comparison with the Troyon scaling and (3) a promising B^2 scaling of the reconnection heating. Those facts indicate that the axial merging is one of the most efficient startup methods for high-beta STs without powerful CS.

在TS-3和TS-4聚变实验中，利用磁场重联的高功率加热，发展了一种新型的超高β球形托卡马克（ST）无CS（中心螺线管）构型。在A型合并中，将两个ST合并在一起以将血浆β增加到β_T[约等于]0.5。高功率加热的重连在短的重连时间内将低β合并ST转化为高β ST。在B型并合中，首先由两个反向环向磁场并合的球标形成扁球FRC，然后通过外加环向磁场转变为超高β（β-r约等于0.8）ST。通过B型合并得到的超高β ST具有反磁环向场和绝对最小B型位形。我们首次对产生的ST进行了BALLOO代码稳定性分析，并得出结论，第一稳定/边际气球稳定区的形成与测量的高n不稳定性几乎一致。两个合并地层的不稳定ST遭受高n磁波动，并在10-30阿尔芬时间内破裂。我们的实验观察确定了气球稳定性窗口与测量的高n不稳定性。随着流速剖面的空心度和压力剖面的宽化，稳定区明显变大。本文还讨论了（2）与Troyon标度相比，由此产生的6-17个ST的归一化β_N，以及（3）有希望的重联加热的B^2标度。这些事实表明，轴向合并是没有强大CS的高β ST的最有效的启动方法之一。

项目成果

Y.Ono, M.Inomoto et al.: "Ultra-High-Beta Spherical Tokamak with Absolute Minimum-B in TS-3 Spherical Torus Experiment"Fusion Energy 2000. (CD-ROM). EX7/5 (2001)

Y.Ono、M.Inomoto 等人：“TS-3 球形环面实验中具有绝对最小值 B 的超高 Beta 球形托卡马克”Fusion Energy 2000。（CD-ROM）。

Y.Ueda, Y.Ono: "Experimental Comparison of Compact RFPs, spheromaks, and STs Using Controlled Current Drive"Nuclear Fusion. 41・8. 981-984 (2001)

Y.Ueda、Y.Ono：“使用受控电流驱动的紧凑型 RFP、spheromak 和 ST 的实验比较” 41・8 (2001)。

村田幸弘, 竹内真也, 俵武志, 小野靖: "イオン温度計測用に拡張されたコンピュータトモグラフィーアルゴリズムの開発"電気学会論文誌A. 122-A, 3. 267-273 (2002)

Yukihiro Murata、Shinya Takeuchi、Takeshi Tawara、Yasushi Ono：“用于离子温度测量的扩展计算机断层扫描算法的开发”日本电气工程师学会汇刊 A. 122-A, 3. 267-273 (2002)

Y. Ono, M. Inomoto, Y. Ueda, T. Matsuyama and Y. Murata: "Fast Compression of Current Sheet during Externally Driven Magnetic Reconnection"Earth, Planets and Space. 53. 521-526 (2001)

Y. Ono、M. Inomoto、Y. Ueda、T. Matsuyama 和 Y. Murata：“外部驱动磁重联期间电流片的快速压缩”地球、行星和空间。

M. Inomoto and Y. Ono: "Formation of Ultra-High-Beta Spherical Tokamak Using a Field-Reversed Configuration"Journal of Plasma and Fusion Research. 76, No. 6. 553-560 (2000)

M. Inomoto 和 Y. Ono：“使用场反转结构形成超高 Beta 球形托卡马克”等离子体与聚变研究杂志。