University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Consorzio RFX, Associazione Euratom-ENEA sulla Fusione, Padova 35127, Italy.
Phys Rev Lett. 2019 Aug 2;123(5):055001. doi: 10.1103/PhysRevLett.123.055001.
We report on the first comprehensive experimental and numerical study of fast ion transport in the helical reversed-field pinch (RFP). Classical orbit effects dominate the macroscopic confinement properties. The strongest effect arises from growth in the dominant fast ion guiding-center island, but substantial influence from remnant subdominant tearing modes also plays a critical role. At the formation of the helical RFP, neutron flux measurements indicate a drastic loss of fast ions at sufficient subdominant mode amplitudes. Simulations corroborate these measurements and suggest that subdominant tearing modes strongly limit fast ion behavior. Previous work details a sharp thermal transport barrier and suggests the helical RFP as an Ohmically heated fusion reactor candidate; the enhanced transport of fast ions reported here identifies a key challenge for this scheme, but a workable scenario is conceivable with low subdominant tearing mode amplitudes.
我们报告了螺旋反向磁场箍缩（RFP）中快离子输运的首次全面实验和数值研究。经典轨道效应主导宏观约束特性。最强的效应源于主导快离子引导中心岛的增长，但残余次主导撕裂模的影响也起着至关重要的作用。在螺旋 RFP 的形成过程中，中子通量测量表明，在足够的次主导模式幅度下，快离子会急剧损失。模拟结果证实了这些测量结果，并表明次主导撕裂模强烈限制了快离子的行为。之前的工作详细描述了一个尖锐的热输运障碍，并提出了螺旋 RFP 作为一种欧姆加热聚变反应堆的候选方案；这里报道的快离子输运增强，为该方案提出了一个关键挑战，但在低次主导撕裂模幅度下，仍可以设想出一种可行的方案。
