Experiments on Gas Jet in the Wendelstein 7-AS Stellarator

Wendelstein 7-AS (W7-AS) pertains to an advanced helical stellarator. A new fu-elling method, the supersonic molecular beam injection (SMBI, named Gas Jet in Germany)system was installed in W7-AS in May 2001 as a cooperation research item co-supported by theNational Nature Science Foundation of China and the Max-Planck Institute of Plasma Physics,Garching, Germany. The experiments of the gas jet with hydrogen or deuterium on W7-AS wereimplemented. The experimental results exhibit the following features such as high fuelling ef-ficiency, stable high-density plasmas and reduction of the recycling fluxes from the vessel wallduring injection. These crucial points show that the new fuelling method can be applied to longand stable discharges.