Divertor Simulation Study Using the GAMMA 10 End-Mirror Cell

In GAMMA 10 which is a tandem mirror machine in Plasma Research Center at University of Tsukuba, divertor simulation studies have been planned and started. This paper describes the recent results of divertor simulation experiment in the GAMMA 10 end-mirror cell. As a part of these experiments, characteristics of end-loss plasma have been investigated by using probes and calorimeters. The diagnostics are installed at two positions, which are separated by 40 cm in the axial direction. In the results, ion temperature of the end-loss flux in GAMMA 10 is much higher than that of other divertor simulators. It is found that heat-flux density can be controlled within the range from 0.4 to 0.8 MW/m2 by changing the ICRF power. In addition, heat flux density has strong dependence on diamagnetism in the central-cell which is time integrated in the plasma duration. While, particle-flux density is proportional to electron line-density in the central-cell. Particle and heat fluxes measured at axially different positions agree well with the calculation results for considering the influence of particle reflection phenomena.