Development of a test facility for divertor cooling techniques and plasma diagnostics

Divertor has been adopted in the current magnetically confined fusion to remove helium ashes produced by D-T fusion reactions from the reactor. The divertor plate in ITER is expected to encounter 10-20 MW/m² heat flux and 10²⁴ /m²/s particle flux; both are several times higher than current fusion devices. Thus, it is necessary to develop efficient divertor cooling techniques which can handle such heat and particle fluxes. In this purpose, we have been constructing a test facility producing the heat and particle fluxes of divertor regions and we will use it to study divertor cooling techniques and to develop divertor plasma diagnostics. The plasma source based on the applied-field magnetoplasmadynamic thruster concept was built and the first plasma was successfully obtained with a 1 kW ignition power supply. In order to provide high heat and particle fluxes as divertor regions, a 100 kW dc power supply will be used in the future. For applying external magnetic field, an NdFeB magnet which can provide B_z = 0.15 T on the axial axis is used. To measure the plasma parameters, Langmuir probe array similar to the KSTAR divertor probe array will be used. The detailed performance and measured plasma parameters will be discussed in a paper.