A comprehensive work of the effects of plasma current and heating schemes on divertor power footprint widths is carried out in the experimental advanced superconducting tokamak (EAST). The divertor power footprint widths, i.e., the scrape-off layer heat flux decay length λq and the heat spreading S, are crucial physical and engineering parameters for fusion reactors. Strong inverse scaling of λq and S with plasma current have been demonstrated for both neutral beam (NB) and lower hybrid wave (LHW) heated L-mode and H-mode plasmas at the inner divertor target. For plasmas heated by the combination of the two kinds of auxiliary heating schemes (NB and LHW), the divertor power widths tend to be larger in plasmas with higher ratio of LHW power. Comparison between experimental heat flux profiles at outer mid-plane (OMP) and divertor target for NB heated and LHW heated L-mode plasmas reveals that the magnetic topology changes induced by LHW may be the main reason to the wider divertor power widths in LHW heated discharges. The effect of heating schemes on divertor peak heat flux has also been investigated, and it is found that LHW heated discharges tend to have a lower divertor peak heat flux compared with NB heated discharges under similar input power. All these findings seem to suggest that plasmas with LHW auxiliary heating scheme are better heat exhaust scenarios for fusion reactors and should be the priorities for the design of next-step fusion reactors like China Fusion Engineering Test Reactor.
実験的先进超导托卡马克（EAST）中开展了等离子体电流和加热方案对偏滤器功率沉积宽度影响的综合研究。偏滤器功率沉积宽度，即刮削层热流衰减长度λq和热扩散宽度S，是聚变反应堆的关键物理和工程参数。在内偏滤器靶板处，对于中性束（NB）和低杂波（LHW）加热的L模和H模等离子体，均证明了λq和S与等离子体电流呈强反标度关系。对于由两种辅助加热方案（NB和LHW）组合加热的等离子体，偏滤器功率宽度倾向于在LHW功率占比较高的等离子体中更大。对NB加热和LHW加热的L模等离子体在外部中平面（OMP）和偏滤器靶板处实验热流分布的对比表明，LHW引起的磁拓扑结构变化可能是LHW加热放电中偏滤器功率宽度更宽的主要原因。此外，还研究了加热方案对偏滤器峰值热流的影响，发现在相似输入功率下，LHW加热放电的偏滤器峰值热流往往低于NB加热放电。所有这些发现似乎表明，采用LHW辅助加热方案的等离子体是聚变反应堆更好的排热方案，应作为中国聚变工程测试反应堆等下一代聚变反应堆设计的优先选择。