Author/Authors :
Maingi، نويسنده , , R. and Sabbagh، نويسنده , , S.A. and Bush، نويسنده , , C.E. and Fredrickson، نويسنده , , E.D. and Menard، نويسنده , , J.E. and Stutman، نويسنده , , D. and Tritz، نويسنده , , K. and Bell، نويسنده , , M.G. and Bell، نويسنده , , R.E. and Boedo، نويسنده , , J.A. and Gates، نويسنده , , D.A. and Johnson، نويسنده , , D.W. and Kaita، نويسنده , , R. J. Kaye، نويسنده , , S.M. and Kugel، نويسنده , , H.W. and LeBlanc، نويسنده , , B.P.، نويسنده ,
Abstract :
We report on the behavior of ELMs in NBI-heated H-mode plasmas in NSTX. It is observed that the size of Type I ELMs, characterized by the change in plasma energy, decreases with increasing line-average density, as observed at conventional aspect ratio. It is also observed that the Type I ELM size decreases as the plasma equilibrium is shifted from a symmetric double-null toward a lower single-null configuration. Type II/III ELMs have also been observed in NSTX, as well as a high-performance regime with small ELMs which we designate Type V. The Type V ELMs are characterized by an intermittent n = 1 magnetic pre-cursor oscillation rotating counter to the plasma current; the mode vanishes between Type V ELMs crashes. Without active pumping, the density rises continuously through the Type V phase, albeit at a slower rate than ELM-free discharges.
Keywords :
NSTX , Particle control , Elm , Edge pedestal , Fueling
