全超导托卡马克装置欧姆放电逃逸电子行为研究

Behaviors of Runaway Electrons Generation on Experiment Advanced Superconducting Tokamak

摘要: 电子发生逃逸在托卡马克等离子体中是较常见的现象，特别是在等离子体破裂阶段，会产生大量的逃逸电子。本工作利用硬X射线监测系统，并结合其它相关诊断系统研究世界上第1个运行的全超导托卡马克（EAST）装置在欧姆放电的不同阶段逃逸电子的行为。研究结果表明：在欧姆放电起始阶段，逃逸电子的初级产生过程占主导地位。随着放电的进行，逃逸电子的次级雪崩过程逐渐增长，在放电后期一直到等离子体破裂阶段，雪崩过程将占据主导地位。等离子体破裂后，因存在较高的环电压而产生了高能逃逸电子拖尾。

Abstract: Plasma disruption on the Tokamak device often generates a lot of runaway electrons. Primary (Dreicer) acceleration and secondary avalanching are two mechanisms responsible for the generation of runaway electrons during disruptions. The behavior of runaway electrons generation was investigated at different phases of discharges on Experiment Advanced Superconducting Tokamak. It is found that primary acceleration is the main mechanism in current ramp-up phase while avalanching played an important role in current quench. In the paper, the diagnostics system is described, and the mechanisms of runaway electrons generation in different phases of discharges are presented by hard X-ray measurement.