Measurement of gas injection efficiency for helium, neon and argon impurities in TEXTOR
The impurity concentration in a plasma depends not only on the production rate but also on the probability that the impurities produced actually enter the confined plasma. After entering the plasma and becoming ionised, impurities move parallel and perpendicular to the field lines. If they are ionised near or outside the last closed flux surface, they may have a very short lifetime in the plasma, thus making an insignificant contribution to radiation or fuel dilution. In earlier experiments in TEXTOR, the parallel diffusion and ion heating was studied. A series of experiments is reported here in which impurities have been puffed into the plasma boundary as gases, and measurements have been taken of the resulting increase in radiation and Z(eff). From these measurements a global figure of gas efficiency has been calculated. It has been found that this gas efficiency varies with the impurity species.
Bibliographic Reference: Article: 18th European Conference on Controlled Fusion and Plasma Physics, Vol. IV (1991) pp. 245-248
Record Number: 199111382 / Last updated on: 1994-12-02
Original language: en
Available languages: en