EFFECT OF WALL CONDITIONING ON NEUTRAL GAS-TRANSPORT IN THE GAS-DYNAMIC CONFINEMENT SYSTEM

The effect of titanium conditioning of the chamber wall on the plasma confinement in a gasdynamic confinement system is studied. After depos iting titanium on the inner surface of the vacuum chamber, the charge- exchange loss of fast ions turns out to be substantially smaller than when there was no wall conditioning. For typical discharge conditions, the temporal and spatial variations in the neutral gas density are me asured experimentally and calculated by using the Monte Carlo transpor t code. A comparison of the numerical results with the experimental da ta shows that the recycling coefficient of the chamber wall coated wit h titanium is close to unity.