Alternative schemes of power deposition with the ergodic divertor on Tore Supra

Two alternative schemes to distribute the energy flux over larger surfaces are proposed and tested at Tore Supra. (i) A good sharing of the energy flux to the pump limiter and the ergodic divertor (ED) is achieved at a reduced stochasticity. (ii) The operation at highest densities with the plasma leaning on the high field side is characterised by the same screening properties and achievable densities as for the standard operation. The results indicate that an efficient heat reduction and screening of impurities can be reached under ED operation. These experiments have partly been carried out in order to test special aspects of the dynamic ED (DED) at TEXTOR.