Investigating the effects of a magnetic field divergence on plasma heat load using the linear divertor simulator TPD-Sheet IV

Abstract

We experimentally examined the effects of a magnetic field on plasma heat load for the attached hydrogen plasma not injecting any impurities using a linear divertor simulator, TPD-Sheet IV. Our results demonstrate that plasma thickness expansion generally exceeded its theoretical value, which excludes cross-field diffusion. The expansion of the plasma-facing area with the magnetic field divergence can be increased above the theoretical value because of additional effects such as cross-field transport. It is necessary to verify this additional effect, which produces a sufficient plasma-wetted area for reducing plasma heat load. In addition, our results confirm that the peak value of the ion flux contributing to the generation of plasma heat load decreases as the magnetic field divergence increases, and its tendency is inversely proportional to the magnetic field divergence. This suggests that the magnetic field divergence can effectively reduce the plasma heat load. Keywords: Divergent magnetic field, Divertor, Heat load, Linear plasma device, Plasma-wetted area