1D Modeling of LHD Divertor Plasma and Hydrogen Recycling
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One dimensional plasma and neutral model of the divertor plasma in Large Helical Device is presented. The plasma is described by stationary fluid equations for electron and ion. The atomic processes such as dissociation of hydrogen molecules released from the divertor plate, ionization of hydrogen atoms, charge exchange and recombination are included in equations of neutrals. This model is intended to be employed in an integrated simulation where an equilibrium of the upstream plasma and plasma-surface interactions at the divertor plate are solved in different numerical codes separately. From the computational point of view, the numerical code for the divertor plasma is developed for 1D flux tube where the boundary conditions of both ends are specified. The calculation time is less than one second and reasonably short to use in future integrated simulations. In the results, interactions between plasma and neutrals and dependence of the energy loss on the plasma density are studied. In low density case, the energy is lost through ionization and charge exchange but the total amount of the loss is small and the impurity loss is negligibly small. In high density case, the ionization loss and impurity cooling become much larger than the charge exchange loss and causes a drop of the heat flux.
- Plasma and Fusion Research
Plasma and Fusion Research (5), S1020-S1020, 2010
The Japan Society of Plasma Science and Nuclear Fusion Research