RESUMO
This Letter provides information on the spatial and temporal structure of periodic eruptions observed in magnetically confined laboratory fusion plasmas, called edge-localized modes (ELMs), and highlights similarities with solar eruptions. Taken together, the observations presented in this Letter provide strong evidence for ELMs being associated with a filamentlike structure. These filaments are extended along a field line, are generated on a 100 micros time scale, erupt from the outboard side, and connect back into the plasma. Such structures are predicted by a theoretical model based on the "ballooning" instability, developed for both solar and tokamak applications.
RESUMO
H-mode plasmas have been achieved on the MAST spherical tokamak at input power considerably higher than predicted by conventional threshold scalings. Following L- H transition, a clear improvement in energy confinement is obtained, exceeding recent international scalings even at densities approaching the Greenwald density limit. Transition is accompanied by an order-of-magnitude increase in edge-density gradient, a marked decrease in turbulence, the efficient conversion of internal electron Bernstein waves into free space waves, and the onset and saturation of edge poloidal rotation.
