Foundations for the theory of transport in thermonuclear fusion plasmas

本研究的目的是为热核聚变反应发生的等离子体输运理论奠定基础。重点讨论了燃烧等离子体与非燃烧等离子体在质量上的差异。例如，核聚变点火本身可能是导致异常输运的等离子体湍流的来源；长相关长度的波动可能对运输产生重大影响；新型输运分岔可能发生在被点燃的等离子体中。该研究对这些问题作出了明确的贡献。核聚变产物的运输就是一个例子。研究发现，当湍流久保数大于1时，α粒子的大轨道效应增强了（与传统认识相反的）跨场输运。深入分析了具有较长径向相关长度的纬向流对湍流输运的典型作用。得到了重新归一化纬向流影响的湍流输运系数的理论公式。还确定了一种新的输运分岔；在这种输运分岔中，径向电场、纬向流和高能粒子起着重要的作用。因此，本研究项目在理解聚变燃烧等离子体的湍流输运方面取得了坚实的进展。

The objective of this research is to form a foundation for the theory of transport of plasmas, in which thermonuclear fusion reaction takes place. In particular, focuses are made upon the issues, for which the burning plasmas show qualitative differences from non-burning plasmas. For instance, the fusion ignition itself could be an origin of plasma turbulence that is responsible for the anomalous transport; fluctuations with long correlation length could have substantial impacts on transport; new type of transport bifurcation could occur in ignited plasmas.The research has made clear-cut contribution for these problems. One example is the transport of fusion-products. It was found that, when the Kubo-number of turbulence is larger than unity, the large-orbit effect of alpha particles enhances (contrary to the conventional knowledge) cross-field transport. Prototypical role of zonal flows, which have long radial correlation length, on the turbulent transport was analyzed thoroughly. Theoretical formula of turbulent transport coefficients, for which the impacts of zonal flows are renormalized, were obtained. A new type of transport bifurcation was also identified; in this transport bifurcation, the radial electric field, zonal flows and energetic particles play essential roles. Thus, this research programme has achieved a firm progress in understanding the turbulent transport in fusion burning plasmas.