The quasilinear turbulent particle and heat transports induced by the impurity mode (IM), driven by the opposite gradients of the core hydrogen and outer , , and ions, are shown to be crucial for plasma confinement in toroidal magnetic configurations. Full gyrokinetic effects of both the main and impurity ions, derived from the kinetic theory, are taken into account. Even in the absence of ion temperature gradient or trapped electron (TE) effects, IM turbulence induces significant particle and heat transports, when the impurity fraction remains at the low levels typically measured in plasma experiment. The small mass mz and large charge number Z ions enhance the turbulent transport induced by the IM turbulence and reduce the excitation threshold. The investigation of the temperature ratio effect shows that the inward impurity and outward main ion particle and heat fluxes as well as the growth rate of IM increase when τz increases. In contrast, the growth rate increases first and then decreases while the fluxes are all increase when τi increases. It is also found that the TEs mainly impact the particle transport, while the impurity ion fraction dominates the particle and thermal transports. Most importantly, the IMs are shown to produce significant outward heat transport and inward impurity transport even in regimes with relatively flat ion temperature profiles.
この論文では、水素イオンと不純物イオンの濃度勾配によって駆動される不純物モード(IM)が、トーラス状磁場配位のプラズマ閉じ込めに重要な役割を果たすことを示しています。IM乱流は、主要イオンと不純物イオンの粒子・熱輸送を引き起こし、プラズマ性能に大きな影響を及ぼします。不純物イオンの質量と電荷数が大きいほど、IMによる輸送が増大し、励起しやすくなることが明らかになりました。