Na Yong-Su, Seo Jaemin, Lee Yoonji, Choi Gyungjin, Park Minseo, Park Sangjin, Yi Sumin, Wang Weixing, Yoo Min-Gu, Cha Minsoo, Kim Beomsu, Lee Young-Ho, Han Hyunsun, Kim Boseong, Lee Chanyoung, Kim SangKyeun, Yang SeongMoo, Byun Cheol-Sik, Kim Hyun-Seok, Ko Jinseok, Lee Woochang, Hahm Taik Soo
Department of Nuclear Engineering, Seoul National University, Seoul, 08826, Republic of Korea.
Princeton University, Princeton, NJ, 08544, USA.
Nat Commun. 2022 Oct 29;13(1):6477. doi: 10.1038/s41467-022-34092-0.
A tokamak, a torus-shaped nuclear fusion device, needs an electric current in the plasma to produce magnetic field in the poloidal direction for confining fusion plasmas. Plasma current is conventionally generated by electromagnetic induction. However, for a steady-state fusion reactor, minimizing the inductive current is essential to extend the tokamak operating duration. Several non-inductive current drive schemes have been developed for steady-state operations such as radio-frequency waves and neutral beams. However, commercial reactors require minimal use of these external sources to maximize the fusion gain, Q, the ratio of the fusion power to the external power. Apart from these external current drives, a self-generated current, so-called bootstrap current, was predicted theoretically and demonstrated experimentally. Here, we reveal another self-generated current that can exist in a tokamak and this has not yet been discussed by present theories. We report conclusive experimental evidence of this self-generated current observed in the KSTAR tokamak.
托卡马克是一种环形核聚变装置，需要等离子体中的电流来产生极向磁场，以约束聚变等离子体。传统上，等离子体电流是通过电磁感应产生的。然而，对于稳态聚变反应堆来说，尽量减少感应电流对于延长托卡马克的运行时间至关重要。已经开发了几种用于稳态运行的非感应电流驱动方案，如射频波和中性束。然而，商业反应堆需要尽量少用这些外部源，以最大化聚变增益Q，即聚变功率与外部功率的比值。除了这些外部电流驱动外，理论上预测并通过实验证明了一种自生电流，即所谓的自举电流。在此，我们揭示了另一种可存在于托卡马克中的自生电流，而目前的理论尚未对此进行讨论。我们报告了在韩国超导托卡马克先进研究装置（KSTAR）中观测到这种自生电流的确凿实验证据。
