Simulation of the Time Behavior of Impurities in JET Ar-Seeded Discharges and its Relation with Sawteething
In previous papers the behaviour of impurities and radiation in JET Ar seeded Elmy H-mode discharges, in which the plasma reaches high confinement values at densities close or even exceeding the Greenwald limit has been studied [1, 2]. The impurity transport with different magnetic configurations and heating schemes has been analyzed in the so called 'after-puff phase' (AP), which is the period featuring good confinement properties that follows the phase of a strong Ar and D2 puffing ('inflow phase', IP). The aim of this paper is a more detailed simulation of the time behaviour of Ar and C (that is the main intrinsic impurity in JET), starting from the IP up to the evolution during the AP. The soft X-rays inverted profiles, now available, allow a better determination of the convective velocity and diffusion coefficient profiles, and a more detailed time analysis of the impurities.