Major disruptions, often caused by locked m/n = 2/1 modes (m/n is the poloidal/toroidal mode number), are great threat to a tokamak fusion reactor and should be mitigated or avoided. The locked 2/1 modes have been unlocked by electrode biasing (EB) for the first time in J-TEXT tokamak experiments. The application of a sufficiently negative EB voltage in plasma edge region quickly changes the phase and amplitude of the locked 2/1 mode and drives the mode to rotate in about 10–30ms. For a larger EB current or a smaller locked mode amplitude, the mode is more easily to be unlocked, revealing a new method for mode unlocking and avoiding plasma disruptions.

重大破坏通常是由锁定的m / n = 2/1模式（m / n是倍体/环形模式编号）引起的，对托卡马克聚变反应堆构成了巨大威胁，应予以缓解或避免。在J-TEXT托卡马克实验中，锁定的2/1模式已通过电极偏压（EB）首次解锁。在等离子边缘区域施加足够负的EB电压会迅速改变锁定的2/1模式的相位和幅度，并驱动该模式旋转约10-30ms。对于较大的EB电流或较小的锁定模式振幅，该模式更易于解锁，从而揭示了一种用于模式解锁和避免等离子体破坏的新方法。