Results and modelling of high power edge radiation cooling in Textor

It has been shown recently on TEXTOR that it is possible to obtain stable discharges with good thermal confinement under quasi-stationary conditions with a cold radiative boundary, by injecting the impurities Ne and/or Si. In the first part the main experimental results are summarized. In the second part a first attempt is presented for the modelling of the basic transport processes in these discharges. This is done by using the codes TRANSP for interpretative simulations and RITM for predictive simulations. We find that the bulk confinement is favorably influenced by the application of edge cooling and a satisfactory agreement is obtained between the predictions of RITM and the experimental results.