Associazione EURATOM/ENEA sulla Fusione, Centro Ricerche Frascati, Frascati 00044, Italy.
Nat Commun. 2010 Aug 10;1:55. doi: 10.1038/ncomms1052.
Progress in thermonuclear fusion energy research based on deuterium plasmas magnetically confined in toroidal tokamak devices requires the development of efficient current drive methods. Previous experiments have shown that plasma current can be driven effectively by externally launched radio frequency power coupled to lower hybrid plasma waves. However, at the high plasma densities required for fusion power plants, the coupled radio frequency power does not penetrate into the plasma core, possibly because of strong wave interactions with the plasma edge. Here we show experiments performed on FTU (Frascati Tokamak Upgrade) based on theoretical predictions that nonlinear interactions diminish when the peripheral plasma electron temperature is high, allowing significant wave penetration at high density. The results show that the coupled radio frequency power can penetrate into high-density plasmas due to weaker plasma edge effects, thus extending the effective range of lower hybrid current drive towards the domain relevant for fusion reactors.
基于环向托卡马克装置中约束的氘等离子体的热核聚变能源研究取得了进展，这需要开发高效的电流驱动方法。以前的实验表明，通过外部发射的射频功率耦合到低混杂等离子体波，可以有效地驱动等离子体电流。然而，在聚变发电厂所需的高等离子体密度下，耦合的射频功率不会穿透到等离子体核心，这可能是因为波与等离子体边缘的强烈相互作用。在这里，我们展示了在 FTU（Frascati Tokamak Upgrade）上进行的实验，这些实验基于理论预测，即在边缘等离子体电子温度较高时，非线性相互作用会减弱，从而允许在高密度下实现显著的波穿透。结果表明，由于等离子体边缘效应较弱，耦合的射频功率可以穿透到高密度等离子体中，从而将低混杂电流驱动的有效范围扩展到与聚变反应堆相关的区域。
