Spontaneous evolution of density peaking factor in TEM turbulence-dominated H-mode plasma on the EAST Tokamak.

Understanding the self-organized behaviour of particle confinement is critical for density control in magnetically confined thermonuclear fusion devices. This paper investigates the spontaneous evolution of density peaking factor in TEM turbulence-dominated ([Formula: see text]) H-mode plasma discharge, and the relationship between broadband turbulence ([Formula: see text] kHz) and particle confinement is experimentally reported for the first time. In the plasma core region ([Formula: see text]) with higher pressure gradient and lower collisionality ([Formula: see text]), TEM turbulence is suppressed by the [Formula: see text] flow, which causes the increase in density peaking factor and the pressure gradient, while the strengthening of the pressure gradient further enhances the [Formula: see text] flow. This positive feedback mechanism finally leads to a scenario where particle confinement continuously improves. Additionally, the positive feedback mechanism can induce the n-ITBs with higher auxiliary heating power. In the plasma outer region ([Formula: see text]) with lower pressure gradient, the pressure gradient does not dominate the evolution of poloidal [Formula: see text] flow, and the positive feedback mechanism does not work. The positive correlation connection between the [Formula: see text] rotation velocity and TEM turbulence intensity radial gradient suggests that the Reynolds stress may contribute to the increase in poloidal [Formula: see text] flow. These findings can help us understand the self-organized behaviours for particle confinement and expand the methods for controlling plasma density.