Enhancement of Fusion Rate by Superthermal Tritium Ions

We propose a new concept of a nuclear fusion reactor. It is based on the enhancement of the DT fusion rate in tokamak plasmas by a superthermal population of Tritium ions heated by ICRH. It was already shown that break-even conditions might be reached [C. Castaldo and A. Cardinali, Phys. Plasmas 17, 072513 (2010)]. Here we show that Q$\approx $20, suitable for nuclear fusion power station, can be achieved in a compact tokamak configuration (major radius R=160cm, minor radius a=55cm, elongation k=1.9, triangularity $\delta $=0.4, q95=3.5), operating with I$_{P}$=8MA plasma current, B$_{T}$=11.3T toroidal field, line averaged plasma density n=5X10$^{20}$m$^{-3}$, and 40{\%} D, 35{\%} H, 25{\%} T concentrations of the Hydrogen isotopes. The burning plasma is obtained by the injection of 15 MW ICRF power, coupled by six antennas, with radiating areas of 0.25m$^2$, at the operating frequency f=125 MHz and toroidal wave number n$_{//}$=4. The heating scenario has been analyzed by the code TORIC, and approximated analytical equilibria are considered. As a result the total fusion power expected for the proposed scenario is about 350MW, with Q$\approx $20, assuming that at least 70{\%} of the fusion power carried by the $\alpha $ particles is absorbed by the electrons in the plasma core so that the expected central plasma temperature is about 10keV.