Model analysis of a detached plasma in the linear divertor simulator TPD-Sheet IV

Divertors are required to remove the impurities such as helium ashes in a magnetic conferment-type fusion reactor. Detached plasma is one of the major systems to suppress the heat load from a core plasma. The electron temperature and density have been measured with the linear divertor simulation device TPDsheet IV. To model the ion density, a zero-dimensional model has been developed for solving the system of rate balance equations. We have confirmed the characteristic of ion density on gas pressure with rate equation. The molecular ion density decreases with the gas pressure, therefore molecular recombination reaction may contribute to detached plasma generation.