Investigation of long time constants of magnetic fields generated by the JT-60SA CS1 module
Investigation of long time constants of magnetic fields generated by the JT-60SA CS1 module
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JT-60SA CS1 模块产生的磁场长时间常数的研究
DOI：
10.1016/j.fusengdes.2018.10.005
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发表时间：
2018
影响因子：
1.7
通讯作者：
Kaname Kizu
中科院分区：
文献类型：
--
作者：
Tetsuhiro Obana;Kazuya Takahata;Shinji Hamaguchi;Hirotaka Chikaraishi;Suguru Takada;AkifumiIwamoto;Shinsaku Imagawa;Toshiyuki Mito;Haruyuki Murakami;Kyohei Natsume;Kaname Kizu
在JT-60SACS1CIC模块的冷态试验中，对由六个八片线圈和一个四片线圈缠绕Nb3SnCIC导体组成的 模块进行了自磁场测量。结果表明，CS1 组件消磁后自磁场有衰减现象。衰减的时间常数在90 S~2 69 S之间。测量结果表明，由于线圈通电，CS1 模块中出现了长时间常数的回路电流。具有长时间常数的回路电流，也称为超流，是导体设计中意想不到的不规则耦合电流。到目前为止，在CIC导体中只在大型超导线圈中观察到具有长时间常数的回路电流。为了验证没有线圈绕组结构的CIC导体中是否存在长时间常数的回路电流，使用短而直的CIC导体测量了自磁场，其中导体末端电连接了一根多股电缆。结果表明，在长度约为1 m的短直CIC导线中，出现了长时间常数在57 S到10 5 S之间的回路电流，测量结果表明，导线长度并不总是与长时间常数的回路电流有关。CIC导体中是否出现具有长时间常数的回路电流取决于导体末端是否存在电流路径。
In a cold test of the JT-60SA CS1 module, which is composed of six octa-pancake coils and one quad-pancake coil wound with Nb3Sn CIC conductors, the measurement of self-magnetic fields generated by the CS1 module was conducted. As a result, the decay of the self-magnetic field was observed after the CS1 module was degaussed. The time constant of the decay was from 90 s to 269 s. The measurement results indicate that loop currents with long time constants occurred in the CS1 module due to coil energization. The loop currents with long time constants, which are also called ‘supercurrents’, are irregular coupling currents that are an unexpected phenomenon from the conductor design.Loop currents with long time constants in CIC conductors have only been observed in large superconducting coils so far. To verify an occurrence of loop currents with long time constants in a CIC conductor without coil winding configuration, self-magnetic fields were measured using a short straight CIC conductor where a multi-strand cable was connected electrically at the conductor ends. As a result, loop currents with long time constants ranging from 57 s to 105 s occurred in the short straight CIC conductor, the length of which is approximately 1 m. The measurement results indicate that the conductor length is not always related to loop currents with long time constants. The occurrence of loop currents with long time constants in the CIC conductor depends on the presence of current paths at the conductor ends.