Some physical problems of RF heated tokamak plasma in a hybrid reactor regime

Conclusion

In our paper we have presented a simple model of lower hybrid heated tokamak operating near to the hybrid reactor regime, based on energy balance considerations. This model enabled us to obtain first quantitative estimates of tokamak and RF source parameters. With respect to the complexity of the physical problems involved, the formulation of even a fully one-dimensional closed model is a long term matter and requires at least rough knowledge of parameter range. From this point of view, the results of our paper might be valuable.

One of the most interesting results of our paper is the estimated magnitude of the driven current, which is close to the induction currents considered in projects of pulsed hybrid reactor tokamaks. This indicates that the attractive idea of a hybrid reactor tokamak is plausible. This possibility has not yet been discussed in the literature enough.

To obtain a more realistic picture of all processes, it is necessary, first of all, to take into account their dynamic character. One can expect that the time dependent solution will result in the change of radial profiles of density and temperature (which in turn leads to the alteration of neutron fluxes) and current density.

As has been mentioned in the foregoing chapters, both the absorption of the RF field and the driven current amplitudes require more thorough studies of the mechanism of the absorption with respect to the real geometry.

Attention must be paid to the behaviour of alpha particles produced in tokamak as well, because their escape can influence the power balance.