等离子体破裂后期逃逸电流耗散与磁动能转换研究

等离子体破裂缓解是目前磁约束聚变等离子体急需解决的关键科学技术问题之一。大型托卡马克装置运行期间具有极大的热能和磁能，这就要求其具有一套高效可靠的破裂缓解系统。近几年等离子体破裂机理和破裂缓解研究方面取得了不少进展，但是逃逸电子的抑制仍然是一个有待解决的关键问题。目前研究表明破裂前大量杂质注入无法避免下一代大型装置上逃逸电子的产生，最有效的措施为逃逸电流产生后将逃逸电流安全耗散。这就需要发展一套有效的逃逸电流耗散技术将存储在逃逸电流中的逃逸电子动能和磁能快速耗散从而实现装置的安全运行。本项目拟结合ITPA MHD组提出的WG-13研究任务，从实验和模拟方面开展大量杂质注入下逃逸电流耗散和磁能转换研究，为下一代装置的安全运行提供参考。

The thermal and magnetic energies stored in large scale tokamak necessitate a highly reliable and efficient mitigation scheme for plasma major disruptions. The mitigation technique that is most advanced and has been chosen for ITER is the injection of high-Z impurities for the dissipation of magnetic, thermal and runaway electron energy. In recent years, substantial efforts have been undertaken in both experiments and modelling to improve the understanding of disruptions, the physics processes involved in mitigation and the optimization of the mitigation efficiency. There is now a much more mature qualitative, but also quantitative, understanding of the mitigation of electromagnetic and thermal loads. However with respect to runaway electrons, identifying a suitable mitigation scheme for ITER presents substantial challenges. Disruption mitigation has to ensure that: a) a high fraction of the thermal energy is radiated, b) the dissipation of magnetic energy is fast enough to prevent heat loads and halo currents, but not so fast as to generate excessively high eddy currents, and c) runaway electron generation is avoided or, if avoidance is not possible, that the magnetic and kinetic energy stored in the runaway beam is dissipated on a fast timescale. In this proposal, we are planning to investigate the dissipation of runaway current and the conversion of magnetic energy into runaway kinetic energy by high Z impurities injection during the runaway current plateau.