环径比为2的托卡马克反应堆中氘氚燃烧等离子体特性

本文对环径比为2（A=2）的托卡马克反应堆中氘氚燃烧等离子体的特性，利用一类简单的平衡位形，即Solov’ev位形，进行了研究。作为基准，采用了Troyon比压极限和Greenwald密度极限，以及 ITER的H-模约束定标关系。我们发现，除了增大拉长比外，大的三角变形也有利于提高比压值及获得高的聚变功率输出。与 ITER设计相比，对相同的总等离子体电流而言，A=2的反应堆因边缘安全因子很大，具有可以避免破裂不稳定性的优点。由于减小环径比时环内侧的可利用空间相应减小，这类反应堆的一个主要缺点是环向磁场强度也会减小，从而降低聚变堆品质。实际研究工作中要对这些方面做出某种折衷。另外，虽然由于我们采用了简单的位形，我们不能对自举电流的准直性进行优化，但是通过本研究仍然可以对中等环径比反应堆系统（目前是研究工作的空白）的特点获得了解。

D－T burning plasma characteristics in an A=2 tokamak reactor

The deuterium--tritium (D--T) burning plasma characteristic in an aspect ratio A=2 tokamak reactor is studied based on a simple equilibrium configuration,the Soloviev-type configuration. Operation limits for the Troyon beta value and for the Greenwald density value as well as for the ITER H-modeconfinement scaling are used as the benchmark. It is found that in addition to suitable elongation, large triangularity has advantage for arriving at high beta value and obtaining high fusion power output. Compared to the present ITER design, the A=2 system can have very good merit for theavoidance of disruptions by setting rather high edge q value while keeping relatively large total toroidal current. The main disadvantage of decreasing the aspect ratio is due to the loss of more useful space in the inward region that leads to the decrease of toroidal magnetic field in the plasmaregion, then worsening the fusion merit. Our analysis and calculation also present a trade-off in this respect. Due to simple equilibrium configuration assumed, some other important issues such as the bootstrap current alignment cannot be optimized. However, the present analysis can offer an insight into the advantages of the medium aspect ratio reactor system that is a blank in present-day tokamak study.