Furno, I.Labit, B.Fasoli, A.Poli, F. M.Ricci, P.Theiler, C.Brunner, S.Diallo, A.Graves, J.P.Podesta, M.Mueller, S.H.2009-01-232009-01-232009-01-23200810.1063/1.2870082https://infoscience.epfl.ch/handle/20.500.14299/34362WOS:000256305200065The mechanism for blob generation is detailed in the toroidal magnetized plasma of the TORPEX device [ Fasoli et al., Phys. Plasmas 13, 055902 (2006) ] using an experimental configuration, which features a plasma region dominated by a coherent wave and a region on the low field side characterized by the propagation of blobs. Predictions from linearized 2D drift-reduced Braginskii equations are compared with experimental data, revealing the interchange nature of the coherent wave. The dynamics of blob formation is investigated using time-resolved measurements of two-dimensional profiles of electron density, temperature, plasma potential and E×B velocity. Blobs form from radially elongated structures associated with the interchange wave. When a blob is generated, the following sequence of events is observed: 1) A decrease of local pressure gradient length provides an increase of the interchange mode drive; 2) in response, the interchange mode increases in amplitude and expands in the radial direction forming a radially elongated structure from the wave crest; 3) the elongated structure is convected by the E×B flow and is eventually sheared off, forming a blob on the low field side. The dependence of the blob amplitude upon the minimum pressure radial scale length before the blob ejection is also investigated.TORPEX grouptext::conference output::conference proceedings::conference paper