The ideal magnetohydrodynamic (MHD) stability of the tokamak edge is analyzed, with particular emphasis on radially localized instabilities; it is proposed that these are responsible for edge pressure gradient limits and edge localized modes (ELMS). Data and stability calculations from DIII-D [to appear in Proceedings of the 16th International Conf…
Low-aspect-ratio tokamaks offer both the economic advantage of smaller size and a number of physics advantages which are not available at conventional aspect ratio. The Small Tight Aspect Ratio Tokamak (START) [Fusion Technology 1990, edited by B. E. Keen, M. Huguet, and R. Hemsworth (North-Holland, Amsterdam, 1991), Vol. 1, p. 353] was conceived a…
Impurities in fusion plasmas lead to a loss of reactivity by radiation and fuel dilution. 1 The impurity concentration in the plasma is determined both by the production rate and transport in the plasma, particularly the transport in the boundary layer. 1'2 In this layer impurities, usually starting as cold atoms or molecules, are ionised and heate…
