Poloidal asymmetries in the ISTTOK edge plasma

Abstract The ISTTOK edge plasma parameters show significant poloidal asymmetries in both equilibrium and fluctuating parameters. Asymmetries favoring the outboard side are observed in density, turbulent particle flux and diffusion coefficient independently of the toroidal magnetic field direction, suggesting a ballooning-like transport. This interpretation is supported by the characteristics of the fluctuations as they are found to be more intermittent on the outboard side. In addition, up/down asymmetries reversing with the reversal of the toroidal magnetic field direction are found. Significant poloidal asymmetries were also measured in the parallel flow that can be attributed mainly to Pfirsch–Schluter flows.