HL-2A等离子体破裂期间逃逸电子行为及其缓解实验研究

For current and future fusion experimental devices, how to ensure the safe operation of the device is the primary key question. A large number of high-energy runaway electrons will be produced during plasma disruptions in tokamak, high-energy runaway electron beam can therefore be formed that constitute a serious threat to tokamak safe operation. For this reason, a very active field of research has opened up during the last two decades on disruption runaway electrons, and has made great progress. However, many problems about disruption runaway electrons have not been fully resolved and still need further research, for example: generation mechanism of disruption runaway electrons, the formation and migration of disruption runaway electrons, and how to effectively mitigate the disruption runaway electron, and so on. In this project, we will further carry out the experimental study of runaway electron behaviour and runaway electron mitigation during disruptions in the HL-2A tokamak. Since plasma auxiliary heating and fueling are the main means in the HL-2A tokamak for the exploring of the H-mode operations, a variety of auxiliary heating systems, fueling systems and plasma diagnostics have recently developed in HL-2A. Moreover, runaway diagnostics have been improved during the National Natural Science Foundation of China (11005036). All of these conditions ensure the successful conduct of our experiments. The studies will have important physical implications for ITER.

对于目前和未来的聚变实验装置来说，如何保证装置的安全运行是首要的关键问题。等离子体破裂期间易产生大量的高能逃逸电子，这些电子形成逃逸束并局域地轰击装置第一壁，这对装置的安全运行构成了致命的威胁。因此，近二十年来国际上很多装置开展了破裂逃逸电子实验研究，并取得了很大进展。但是，破裂逃逸电子的很多问题还没有完全解决，仍需深入研究，例如：不同产生机制在破裂逃逸电子产生中的作用，逃逸电子束的形成和迁移，如何有效地缓解破裂逃逸电子等。本项目将在HL-2A装置上对破裂逃逸电子行为进行系统研究并深入探索有效的破裂逃逸电子缓解手段。HL-2A配备有多种高功率辅助加热及补充加料系统和丰富的诊断系统，同时我们在青年科学基金项目（11005036）期间发展和完善了逃逸电子诊断系统，这使得我们可以在HL-2A上深入开展破裂逃逸电子行为及其缓解实验研究。这些研究对于ITER具有重要的物理意义。

逃逸电子物理以及发展有效的控制手段是当前托卡马克等离子体物理研究的热点之一。本项目在HL-2A装置完善和发展了三套逃逸电子诊断系统，主要包括：研制了BGO硬X射线测量系统，建立高速可见光相机系统和完善红外相机系统，为破裂逃逸电子实验研究提供完善的实验平台。在HL-2A装置开展了破裂逃逸电子实验研究，主要包括：等离子体破裂期间逃逸电流平台实验研究和磁扰动对逃逸电子产生的影响。利用LHCD，LBO，MGI和RMP实验研究了LHCD对逃逸电子产生增强，磁扰动抑制或避免破裂逃逸电子产生，破裂逃逸电子束产生和逃逸电流平台的形成。