Start-Up and Formation of Spherical Tokamak Equilibria by Electron Bernstein Wave Current Drive

电子伯恩斯坦波电流驱动球形托卡马克平衡的启动和形成

• 批准号: 14208053
• 负责人: MAEKAWA Takashi
• 金额: $ 24.54万
• 依托单位: Kyoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14208053/
• 关键词: Spherical Tokamak; Electron Bernstein Wave; Electron Cyclotron Heating; Low Aspect Ratio Torus; Electron Cyclotron Current Drive; ECH; ECCD; Magnetic Fusion; 電子バースタイン波; 電流駆動

Main objective of the research is to demonstrate formation of ST plasmas by electron cyclotron heating(ECH) alone without center solenoid. By the electron cyclotron heating via mode-converted electron Bernstein wave from microwave power, low aspect ratio torus (or Spherical Tokamak) plasmas can be started-up and formed in the LATE (Low Aspect ratio Torus Experiment) device. The main results are followings.1.Spontaneous formation of ST equilibria under steady Bv fields, where plasma current increases rapidly in the time scale of a few milliseconds, is also effective and a plasma current of 6.8 kA is spontaneously generated and maintained at Bv=85 Gauss by a 5 GHz microwave pulse (130 kW, 60 ms).2.By injecting a 2.45 GHz microwave pulse up to 30 kW for 2 seconds, a plasma current is spontaneously initiated under a weak steady vertical field, and then ramped up with slow ramp-up of Bv for the equilibrium of the plasma loop and finally reaches 7.2 kA at Bv=80 Gauss. This currents amount 12 % of the coil currents of 60 kAT for the toroidal field. Magnetic measurements show that an ST equilibrium, having the last closed flux surface with an aspect ratio of R0/a=20.4 cm/14.5 cm=1.4, an elongation of K=1.6 and qedge=33,has been produced and maintained at the final stage of discharge.3.In both above two cases the plasma center locates near the second harmonic EC resonance layer and the line averaged electron density exceeds twice the plasma cutoff density, suggesting that the second harmonic EC heating by the mode-converted electron Bernstein waves(EBW) supports the plasma. Polarization adjustment of incident electromagnetic waves is proposed for optimal mode-conversion to electron Bernstein waves and is shown to be effective.

该研究的主要目的是证明单独通过无中心电磁阀的电子回旋加热（ECH）形成了ST等离子体。通过通过微波功率转换的电子伯恩斯坦波的电子回旋加热，可以启动低宽高比圆环（或球形tokamak）等离子体，并在晚期（低纵横比圆环实验）设备中形成。 1.在稳定的BV场下，ST均衡的显着形成，在几毫秒的时间尺度上，血浆电流迅速增加，也有效，血浆电流为6.8 ka的血浆电流自发地产生和维持在BV = 85 Gauss的55 GHz Microwave Mirtowave pulse（130 ks）。 30 kW持续2秒钟，在弱稳定垂直场下自发启动等离子体电流，然后以BV缓慢升高，以使血浆环的平衡升高，并在BV = 80 Gauss时达到7.2 ka。该电流为环形场的60 KAT线圈电流的12％。磁性测量表明，在纵横比为r0/a = 20.4 cm/14.5 cm = 1.4的纵横比的最后一个闭合通量表面，伸长k = 1.6和QEDGE = 33，并保持在排放的最后一个阶段。3。在两种情况下，等离子中心附近的二层均应层均超过二层。截止密度，表明由模式转换的电子伯恩斯坦波（EBW）进行第二次谐波EC加热支持血浆。提出了入射电磁波的极化调节，以最佳的模式转换到电子伯恩斯坦波，并被证明是有效的。

项目成果

Start-Up and formation of Spherical Tokamak Equilibria by ECH in the LATE Device

LATE 装置中 ECH 的启动和球形托卡马克平衡的形成

• 期刊: Proc., 20^<th> IAEA Fusion Energy Conf.(Vilamoura, Portugal, 1-6 November 2004) Number IAEA-CN-116/EX/P4-27
• 作者: T.Maekawa;H.Tanaka;M.Uchida et al.
• 通讯作者: M.Uchida et al.

M.Uchida, H.Tanaka, T.Maekawa et al.: "Start-Up of Spherical Torus by ECH without Central Solenoid in the LATE Device"Journal of Plasma and Fusion Research. Vol.80. 83-84 (2004)

M.Uchida、H.Tanaka、T.Maekawa 等人：“在 LATE 装置中通过 ECH 无需中央螺线管启动球形环面”等离子与聚变研究杂志。

Spontaneous Formation of Low-Aspect-Ratio Torus Equilibrium by ECH under Steady Vertical Field

稳定垂直场下 ECH 自发形成低展弦比环面平衡

• 发表时间: 2005
• 期刊: Journal of Plasma and Fusion Research Vol.81 No.5(in press)
• 作者: T.Yoshinaga;M.Uchida;H.Tanaka;T.Maekawa
• 通讯作者: T.Maekawa

H.Igami, M.Uchida, H.Tanaka, T.Maekawa: "Polarization Adjustment of Incident Electromagnetic Waves for Optimal Mode-Conversion to Electron Bernstein Waves."Plasma Physics and Controlled Fusion. Vol.46. 261-275 (2004)

H.Igami、M.Uchida、H.Tanaka、T.Maekawa：“入射电磁波的偏振调整，以实现电子伯恩斯坦波的最佳模式转换。”等离子体物理和受控聚变。