Particle recirculation studies in JET

A global particle balance analysis has been applied to a variety of L-mode and H-mode deuterium discharges of the C4 campaign of JET, performed at a lower wall temperature, in different magnetic configurations and with various divertor gas puffing location. Wall retention and divertor particle exhaust are discussed as a function of the plasma configuration, the wall temperature and the gas puffing location. The effect on ELMs frequency is also mentioned. A simple empirical law linking the divertor pressure and the Dα signal integrated on the divertor is derived, which allows one to estimate the inner and outer contribution to pumping.