Gross particle confinement characteristics by the boundary plasma in the JFT-2 Tokamak

The boundary plasma of a Tokamak device is investigated experimentally by using an electrostatic probe. It is shown that the density of the boundary plasma decays exponentially in the radial direction and perpendicular diffusion in the boundary plasma behaves like the Bohm type. The gross particle confinement time is evaluated from the particle flux to the limiters and the wall, which can be estimated from the density profile and the electron temperature of the boundary plasma.