聚变等离子体中的快离子压强

FAST ION PRESSURE IN FUSION PLASMA

本文运用Fokker-Planck方程的慢化近似,考虑存在多种离子成份(包括杂质),假定它们具有共同的温度,我们得到了聚变产生的快离子压强的简单封闭形式表示式。表明在典型的工作温度下(～60keV),D-~3He等离子体中聚变产生的快离子压强约为本底热压强的20％,这与D-T等离子体工作在20keV时的比值几乎相同。因此,D-~3He和D-T在它们相应的预期工作温度下,它们各自的快离子压强对总压强的影响是类似的,然而在更高的温度下,这个比值将变得更大。

The pressure due to fusion-born fast ions is calculated using the slowing down approximation to the Fokker-Planck equation. The analysis considers multiple ion species, including impurities. The various ion species are assumed to have the same temperature, but may have different charges and masses. A simple closed-form expression for the pressure is obtained. Some results for D-T and D-3He plasmas are given. It is found that the fast ion pressure in a D-3He plasma at a typical plasma temperature of 60 keV is about 20% of the thermal pressure; this is about the same percentage in a D-T plasma at 20 keV. Consequently, the impact of fast ions on the total pressure is similar for D-T and D-3He plasmas at their expected operating temperatures. At elevated temperatures, however, the fast ion pressure can become a larger fraction of the total pressure.