title: Stationary Zonal Flows during the Formation of the Edge Transport Barrier in the JET Tokamak.
abstract: High spatial resolution Doppler backscattering measurements in JET have enabled new insights into the development of the edge Er. We observe fine-scale spatial structures in the edge Er well with a wave number krρi≈0.4-0.8, consistent with stationary zonal flows, the characteristics of which vary with density. The zonal flow amplitude and wavelength both decrease with local collisionality, such that the zonal flow E×B shear increases. Above the minimum of the L-H transition power threshold dependence on density, the zonal flows are present during L mode and disappear following the H-mode transition, while below the minimum they are reduced below measurable amplitude during L mode, before the L-H transition.
authors.affiliation: CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom.
authors.forename: J C
authors.initials: JC
authors.lastname: Hillesheim
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA.
authors.forename: E
authors.initials: E
authors.lastname: Delabie
authors.affiliation: CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom.
authors.forename: H
authors.initials: H
authors.lastname: Meyer
authors.affiliation: CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom.
authors.forename: C F
authors.initials: CF
authors.lastname: Maggi
authors.affiliation: Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.
authors.forename: L
authors.initials: L
authors.lastname: Meneses
authors.affiliation: Max-Planck-institut fur Plasmaphysik, Garching, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Poli
authors.affiliation: CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom.|Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA.|Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.|Max-Planck-institut fur Plasmaphysik, Garching, Germany.
authors.lastname: Jet Contributors