Designing an upgrade of ohmic heating system for the QUEST spherical tokamak
Designing an upgrade of ohmic heating system for the QUEST spherical tokamak
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DOI：
10.1016/j.fusengdes.2021.112362
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发表时间：
2021-07
影响因子：
1.7
通讯作者：
Yifan Zhang;T. Onchi;K. Nakamura;Akihiro Kidani;Qilin Yue;K. Kuroda;M. Hasegawa;R. Ikezoe;H. Idei
中科院分区：
文献类型：
--
作者：
Yifan Zhang;T. Onchi;K. Nakamura;Akihiro Kidani;Qilin Yue;K. Kuroda;M. Hasegawa;R. Ikezoe;H. Idei
升级的欧姆加热(OH)系统具有双极电路，设计成可以实现100kA以上的等离子体电流，理想情况下不会在QUEST球形托卡马克中产生涡流影响。IGBT(绝缘栅双极晶体管)堆叠起到开关的作用，可以改变OH一次电流的极性，最高可达±8kA。新的OH的一个主要目标是为8.56 GHz的电子回旋(EC)波产生过密集的等离子体。用电子伯恩斯坦波加热可以在这种过高密度的等离子体中进行。通过对磁场和磁通面的分析，研究了通过中心螺线管的电流摆动在真空室中产生的涡流对零点的影响。在初始阶段，流过真空室的涡流将零点移动到多个EC共振层所在的高磁场一侧。
An upgraded Ohmic heating (OH) system with a bipolar circuit is designed to achieve plasma current over 100 kA ideally without the effect of eddy current in the QUEST spherical tokamak. IGBT (Insulated Gate Bipolar Transistor) stacks work as switches to change the polarity of OH primary current up to ±8 kA. A main target of the new OH is to generate over-dense plasmas for the 8.56 GHz electron cyclotron (EC) wave. Heating with electron Bernstein waves can be conducted in such over-dense plasmas. The effect of eddy current flowing in the vacuum vessel, which is generated by the current swing through the central solenoid, on null point is investigated by analysis of magnetic field and flux surfaces. In the initial phase, eddy current flowing through the vacuum chamber shifts the null point to the high magnetic field side where multiple EC resonance layers are located.