Density limits and evolution of disruptions in ohmic TEXTOR plasmas
Density limits and the evolution of disruptions were studied on TEXTOR for different wall materials facing the plasma surface. A systematic extension of the density limit was found over a large current range when the metallic wall was first exchanged by a carbon coated wall and later by a boron-carbon coated wall. The maximum attainable density nearly doubled when metallic impurities were replaced by low Z impurities such as boron and carbon. With a neutral beam additional heating power of P(NI) = 3.2 MW, average densities exceeding n(e)bar = 1.0 E20/m3 were obtained. The maximum density observed scales as the square root of the auxiliary heating power. The experimental data obtained for the different materials are presented, and ohmic and neutral beam heated plasmas are compared. The physical processes leading to the major plasma disruption, and its time evolution, are also described.
Bibliographic Reference: Article: Nuclear Fusion, Vol. 32 (1992) No. 4, pp. 645-654
Record Number: 199211076 / Last updated on: 1994-11-29
Original language: en
Available languages: en