Abstract: The principle of magnetic measurements on the concentric coils of HL-2A tokamak, and the design of concentric circles system are introduced, including identification of the area difference for the coils and integral circuit design. Through an effective compensation for stray magnetic field, concentric circles diamagnetic measurement system can get a higher signal-to-noise ratio, and therefore reliable plasma diamagnetic signal in complex discharge conditions can be obtained.

Key words: Concentric diamagnetic coils, Poloidal beta, Vertical average kinetic energy, Energy confinement time

摘要： 介绍了HL-2A装置上同心圆逆磁测量的原理以及同心圆系统的设计，包括线圈面积差的确定和积分电路的设计。对实验数据的分析表明，通过对杂散场的有效补偿，同心圆逆磁测量系统可获得较高的信噪比，能够在一些较复杂的放电条件下可靠地获取等离子体逆磁信号。

关键词: 同心圆逆磁线圈, 极向比压, 垂直平均动能, 能量约束时间