Comparative Analysis of Radial Plasma Parameters and Electric Field Shear With and Without the Edge Transport Barrier Formation in SSDT Devices

Abstract

In magnetic confinement reactors, the radial electric field and its shear are very important for edge transport barrier (ETB) formation and turbulence suppression. In the present work, a multifluid transport code, B2SOLPS5.02D, was used to model the radial distribution of plasma parameters (such as electron density, electron temperature, and ion velocity), radial electric field, and its shear in both cases with and without the ETB formation in small size divertor tokamak (SSDT) devices. The results demonstrated that the radial electric field in the ETB mode is similar to the neoclassical electric field near the separatrix. A toroidal rotation was observed in the co-current/counter-current directions in the discharge without/with the ETB, respectively. An intense radial electric field shear developed, resulting in a significant reduction in the transport coefficient. The ETB region appeared to be located between the maximum and minimum values of the radial electric field shear. Furthermore, the results demonstrated that the ETB width was proportional to the ion temperature and inversely proportional to the radial electric field shear. The impact of the radial electric field shear on the diffusion coefficient, plasma density, and ETB formation was investigated.