Abstract:

A radiofrequency (RF) ion source with beam power of 1 MW is developed for the neutral beam injector on the HL-2A tokamak. At present, this ion source can deliver a 35keV/12.4A hydrogen ion beam for 100 ms on the test-bed, reaching 44% of its design beam power. The proton proportion of the beam is 79%. The energy density profile of beam is measured with infrared imaging technique for beam characteristic evaluation. It is found that at a transportation distance of 1.3 m the beam density profile obeys a Gaussian distribution. The optimum beam perveance is about 1.689×10^–6A•V^-3/2 and it varies slightly with the RF power. According to the experimental results, some related measures have been taken to improve the beam performances of the ion source.

Key words: RF ion source, Neutral beam injection, Beam characteristics

摘要：

介绍了为HL-2A 装置设计的引出束功率为1MW 的射频离子源研制情况。目前，在测试平台上，该离子源已经成功引出了束能量和束电流分别为35keV 和12.4A、束质子比为79%、脉宽为100ms 的氢离子束，达到了其设计束功率的44%。用红外热成像的方法测量了离子束能量密度分布。结果表明，在距离引出系统地电极 1.3m 处，束密度分布遵循高斯分布。引出束的最佳导流系数为1.689×10^–6A•V^-3/2 左右，随射频功率改变有较小的变化。根据这些实验结果，采取了相关改进措施来改善离子源的引出束性能。

关键词: 射频离子源, 中性束, 束流特性