Investigation of transport-relevant fluctuations in the plasma boundary of ASDEX

After the discussion of plasma diagnostics the local radial particle flux in the plasma edge is described, followed by a treatment of the density and potential fluctuations in the boundary zone. A statistical analysis determines the correlation lengths of the observed fluctuations in directions poloidal, radial and parallel to the magnetic field. Power density spectra and coherent spectra lead to better understanding of the fluctuations. The asymmetry of the fluctuation amplitude between high and low field side of the torus has been observed in a tokamak for the first time. Furtheron the dependence of the fluctuation properties on global plasma parameters is examined, together with the extremely high flucutations' correlation along the magnetic field lines. The response of the fluctuations to additional heating by neutral beam injection is elaborated, especially in the H-mode of better plasma confinement. ASDEX fluctuations are compared with such of other machines, followed by a survey of the manifold instabilities and their properties. The appendix discusses the divertor tokamak ASDEX and the applied statistical methods. (AH)