Density limits and disruptions in the TCA tokamak
Density limit disruptions have been studied during the current flat-top of TCA. Disruption occurs at two different densities, depending on discharge programming. The highest densities are achieved by a strong influx of neutral gas called hard gas puffing. This allows the plasma density to cross a range which is otherwise unstable and to reach a second region of stability with a high internal inductance. When disruption occurs after hard gas puffing, the internal inductance decreases in time, in contrast to a slower density rise where the inductance increases continuously. The character of the disruptions depends also on the safety factor at the plasma edge, q(a); the disruptions are much more severe for values of q(a) less than 3, while the density limit is often non-disruptive for large q(a). At large values of q(a) greater than or equal to 4.5 the density is limited by increased mode activities.
Bibliographic Reference: Article: Nuclear Fusion, Vol. 32 (1992) No. 10, pp. 1735-1753
Record Number: 199310017 / Last updated on: 1994-11-29
Original language: en
Available languages: en