Improvements to the High-Field-Side Transient CHI System on QUEST
Improvements to the High-Field-Side Transient CHI System on QUEST
复制标题
QUEST 上高场侧瞬态 CHI 系统的改进
DOI：
10.1007/s10894-022-00338-4
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发表时间：
2022
影响因子：
1.1
通讯作者：
Murakami S.
中科院分区：
文献类型：
--
作者：
Kuroda K.;Raman R.;Hasegawa M.;Onchi T.;Hanada K.;Ono M.;Nelson B. A.;Rogers J.;Ikezoe R.;Idei H.;Ido T.;Mitarai O.;Nagata M.;Kawasaki S.;Nagata T.;Higashijima A.;Shimabukuro S.;Niiya I.;Sekiya I.;Kojima S.;Nakamura K.;Takase Y.;Murakami S.
瞬态同轴螺旋度注入（CHI）是低展弦比托卡马克无螺线管等离子体电流启动的一个很有前途的候选方案。在QUEST上进行瞬态CHI研究的目的是开发与反应堆相关的CHI设计。在QUEST上，CHI放电通过沿着磁场线驱动电流来启动，该磁场线将电绝缘电极板（其被称为偏置电极）连接到球形托卡马克底部区域处的容器组件。在CHI在QUEST上的第一次应用中，电绝缘电极板在被称为低场侧（LFS）注入的配置中相对于外部容器偏置。为了在整个放电过程中保持较窄的注入器通量足迹宽度，QUEST现在正在开发一种高场侧（HFS）注入配置，其中电绝缘电极板相对于内部容器组件偏置。通过实施一个CHI专用的气体注入系统，在HFS注入配置的研究，现在已经证明了良好的磁通量演变到真空容器。已经实现了高达43 kA的环形电流，并且所产生的电流与连接电极的磁通量成比例地增加。这些结果表明，与CHI缩放协议表明，更高水平的环形电流可以产生在一个优化的CHI系统中，其中连接CHI电极的磁通量进一步增加的QUEST。
Transient coaxial helicity injection (CHI) is a promising candidate for solenoid-free plasma current start-up in a low-aspect-ratio tokamak in support of developing fully non-inductive scenarios. The aim of the transient CHI research on QUEST is to develop a reactor-relevant CHI design. On QUEST, a CHI discharge is initiated by driving current along magnetic field lines that connect an electrically insulated electrode plate (which is referred to as a bias electrode) to a vessel component at the bottom region of the spherical tokamak. In the first application of CHI on QUEST, the electrically insulated electrode plate was biased with respect to the outer vessel in a configuration referred to as low-field-side (LFS) injection. To maintain a narrow injector flux footprint width throughout the discharge, QUEST is now developing a high-field-side (HFS) injection configuration, in which the electrically insulated electrode plate is biased with respect to the inner vessel components. Through the implementation of a CHI-dedicated gas injection system, studies in the HFS injection configuration have now demonstrated good magnetic flux evolution into the vacuum vessel. Toroidal currents up to 43 kA have been achieved, and the generated current has increased in proportion to the magnetic flux connecting the electrodes. These results which show agreement with the CHI-scaling suggest that much higher levels of toroidal current can be generated on QUEST in an optimized CHI system in which the magnetic flux connecting the CHI electrodes is further increased.