Images of Impurity Line Emission in the Extreme Ultraviolet Region From the Large Helical Device With an Edge Stochastic Magnetic Field Layer

In fusion research, the stochastic magnetic field with 3-D magnetic field structure formed at the plasma edge has been energetically investigated to mitigate the divertor heat load. The edge stochastic magnetic field layer in the large helical device, which is intrinsically provided by a unique coil system for the plasma confinement, has also been studied for steady-state radiative divertor operation using impurity radiation. Therefore, impurity transport study in the 3-D magnetic field is crucially important. Images of impurity line emission in an extreme ultraviolet range are observed for the edge impurity transport study.