Dynamic transport study of heat and momentum transport in a plasma with improved ion confinement in the Large Helical Device

Dynamic transport study taking account of the slowing-down effect on the neutral beam injection heating is applied to a high ion temperature plasma with an ion internal transport barrier (ITB) obtained by carbon pellet injection, which records the highest ion temperature of around ~7 keV in the Large Helical Device. The transient increase in ion heating is clarified during the density decay phase just after the carbon pellet injection by considering the slowing-down effect. The dynamic transport analysis also includes the change in heat flux due to the change in kinetic energy inside the plasma with the time scale of the global energy confinement time, which is required to investigate the heat and momentum transport during the transient phase more exactly. The characteristics of the ion heat and momentum transport improvement during the ion ITB formation phase are clarified by the dynamic transport study.