An attached poloidal current, which flows in a circuit lying partly in the vacuum vessel wall and partly in the scrape-off layer of the plasma, is observed during vertical instabilities in the DIII-D tokamak. A direct measurement of the current, using Rogowski loops on several protective tiles at locations where the plasma contacts the wall, is in good agreement with the value determined from MHD equilibrium reconstructions using measured values of magnetic field and flux. This attached current, which can reach transient peaks of several hundred kiloamperes, interacts with the toroidal magnetic field to create a large vertical force on the vacuum vessel. The predicted motion of the vessel resulting from the measured currents agrees well with the observed displacement of the vacuum vessel.
垂直不稳定性期间，在DIII-D托卡马克中观察到一种附着极向电流，该电流流经部分位于真空室壁内、部分位于等离子体刮削层中的回路。使用位于等离子体与壁接触位置的多个保护瓦片上的罗戈夫斯基线圈直接测量该电流，其结果与利用实测磁场和磁通值进行MHD平衡重建所确定的值吻合良好。该附着电流可达到数百千安培的瞬态峰值，其与环向磁场相互作用，在真空室上产生巨大的垂直力。由实测电流预测的真空室运动与观测到的真空室位移吻合良好。