High beta plasma confinement study on a small torus device with a floating high temperature superconductor coil

我们的目标是研究高β等离子体在一个小型的环形装置与高温超导线圈。从等离子体实验和装置操作的观点出发，我们采用了高温超导电缆Bi-2223，它与低温超导体相比具有大的热容。这是将高温超导线圈应用于聚变等离子体装置的第一个挑战，高温超导线圈的反馈悬浮几乎没有挑战。我们已经开始了内部线圈装置Mini-RT的几个研发问题;例如，在微型装置FB-RT上实现了高温超导线圈的悬浮，并在一小时内实现了10 μ m的悬浮精度。由于内部线圈周围的典型磁场为0.1T，因此通过2.45 GHz微波的电子回旋加热（ECH）产生并加热等离子体。等离子体密度为（5-7）× 10 - 4 μ <16>m-2<-3>，并达到微波的截止密度。密度分布在内部线圈附近有一个峰值。电子和离子温度分别为10 eV和1 eV。

We are aiming at studying high-beta plasmas on a small torus device with a high temperature superconductor coil. From the viewpoint of plasma experiment and device operation, we have employed a high temperature superconducting cable Bi-2223, which has a large heat capacity in comparison with a low temperature superconductor. This is a first challenge for applying the high temperature superconductor coil in fusion plasma devices, and there are few challenges for the feedback levitation of the high temperature superconductor coil.We have started several R&D issues for the internal coil device Mini-RT ; e.g., the demonstration of the levitation with the miniature device FB-RT, the design and fabrication of the persistent current switch (PCS) and the demonstration of the persistent current operation, and developments of demountable transfer tube and current feed-through.In the Mini-RT device, we have successfully levitated the high temperature superconductor coil with an accuracy of 10 micrometer during a hour. Since the typical magnetic field is 0.1T around the internal coil, the plasma is produced and heated by the Electron Cyclotron Heating (ECH) with the microwave of 2.45 GHz. The plasma density is (5-7)x10^<16> m^<-3>, and is reaching at the cut-off density of the microwave. The density profile has a peak near the internal coil. The electron and ion temperatures are 10 eV and 1 eV, respectively.