New Electromagnetic Measurement Using High-Temperature Superconducting Coil

为了实现安全、经济的聚变反应堆，需要稳定的等离子体运行。在这种情况下，等离子体能量的实时测量和磁组态的反馈控制是重要的。对于等离子体能量的实时测量，目前采用的是传统的抗磁传感器。为了将其应用于长脉冲操作，需要新的想法或研发。对于等离子体能量的稳态和实时测量，有几种方法；(1)传统抗磁传感器；(2)超导线圈系统的利用；(3)高温超导传感器系统的新方法。特别是，我们一直在开发螺旋约束系统的新方法。在方法(1)的情况下，由于集成电路的特性，不可能测量超过几十分钟的时间。在情形(2)中，由于线圈电源和可控硅的噪声，等离子体能量的测量不容易，特别是在正常导电线圈系统的情况下，本研究开展了大型螺旋装置（LHD）中低温超导线圈利用率测量的研究与开发。演示了高温超导传感器Bi2223的抗磁测量方法。此外，作为这一援助研究的延伸，一种新的紧凑和球形螺旋磁结构已经被探索。

In order to realize safe and economic fusion reactors, steady-state plasma operation is required. In this case, rea-time measurement of plasma energy and the feedback control of magnetic configuration is important. For the real-time plasma energy measurement, conventional diamagnetic sensors has been used so far. To apply this to long-pulse operations, new ideas or R&D's are required.For steady-state and real-time measurement of plasma energy there are several methods ; (1)conventional diamagnetic sensor, (2)the utilization of super-conducting coil system, and (3)novel method utilizing high-temperature superconducting sensor systems. Especially, we have been developing novel methods for helical confinement systems.In the case of method (1),it is impossible to measure more than several tens of minutes due to the property of integral circuits. In case (2),it is not easy to measure the plasma energy because of noise from coil power supply and SCR, especially in the case of the normal conducting coil systemIn this research, R&D of the measurement of the utilization of low-temperature superconducting coil in the Large Helical Device (LHD) has been carried out. The demonstration of the diamagnetic measurement method using the high-temperature superconducting sensor Bi2223 has been demonstrated. Moreover, as an extension of this Grand-In-Aid Research, a novel compact and spherical helical magnetic configuration has been explored.