Abstract:

Gas target thickness for neutralizer is theoretically calculated for the 1MW NBI of HL-2A tokamak with iterative method, and the correspondingly neutralization efficiency is obtained, it is turned out that it is unable to make the neutralization efficiency reach its optimum value only depending on the flowing gas from the ion source, thus it is necessary to add a complementary gas puff in the neutralizer to increase the gas target thickness. The complementary gas puff system has been successfully operated in the 1MW NBI on HL-2A tokamak and the neutralization efficiency can be increased about 10% for the samedischarge parameters.

Key words: NBI, Neutralization efficiency, Gas target thickness, Complementary gas puff

摘要：

采用迭代法对HL-2A装置1MW中性束系统中的中性化气体靶厚进行了理论计算，并给出了相应的中性化效率，发现仅靠离子源顺流气体形成的气体靶通常不能使中性化效率达到最佳值，因而有必要在中性化器内加入补充送气来提高气体靶厚。采用补充送气系统，在相同的放电参数下中性化效率提升约10%。

关键词: 中性束, 中性化效率, 气体靶厚, 补充送气